android - Androidホームスクリーンの開発

Question

ホーム画面のあるアプリに取り組んでいます。このホーム画面は、タッチスクリーン上で指を動かすことで複数のビューを切り替えることができるAndroidホーム画面のように動作する必要があります。

解決策は簡単です。右、左、現在の3つのビューインスタンスがあります。このインスタンスは、以前に初期化したビューフリッパーから取得します。私はHTCG1を持っているので、私の画面は幅320ピクセル、高さ480ピクセルです。

画面に触れたときにアクションダウンモーションイベントのダウン値をキャプチャするとします。次に、指を動かすと、画面がまったく同じように動くはずなので、ビューの位置を再計算する必要があります。これまでのところうまくいきますが、奇妙な問題に直面しています。指を動かさずに右側のビューに触れたが、画面上に1秒未満保持すると、ビューが消えて左側のビューが表示されます。

これが私のコードです：

public class MainActivity extends Activity implements OnTouchListener{

    private ViewFlipper vf;
    private float downXValue;
    private View view1, view2, view3;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        this.vf = (ViewFlipper) findViewById(R.id.flipper);

        if(this.vf != null){
             this.view1 = vf.getChildAt(0);
             this.view2 = vf.getChildAt(1);  
             this.view3 = vf.getChildAt(2);
             vf.setDisplayedChild(0);
         }      

         LinearLayout layMain = (LinearLayout) findViewById(R.id.layout_main);
         layMain.setOnTouchListener((OnTouchListener) this);
    }

    public boolean onTouch(View v, MotionEvent arg1) {

         final View currentView = vf.getCurrentView();
         final View leftView, rightView;

         if(currentView == view1){
             leftView = view3;
             rightView = view2;
         }else if(currentView == view2){
             leftView = view1;
             rightView = view3;
         }else if(currentView == view3){
             leftView = view2;
             rightView = view1;
         }else{
             leftView = null;
             rightView = null;
         }

         switch (arg1.getAction()){
            case MotionEvent.ACTION_DOWN:{
                this.downXValue = arg1.getX();
                break;
            }
            case MotionEvent.ACTION_UP:{
                float currentX = arg1.getX();            
                    if ((downXValue < currentX)){
                        if(currentView != view3){
                        float t3 = (320-(currentX-downXValue))/320;                             
                        this.vf.setInAnimation(AnimationHelper.inFromLeftAnimation(t3));
                        this.vf.setOutAnimation(AnimationHelper.outToRightAnimation(t3));
                        this.vf.showPrevious(); } 
                      }

                    if ((downXValue > currentX)){
                        if(currentView != view2){
                        float t = (320-(downXValue-currentX))/320;
                        this.vf.setInAnimation(AnimationHelper.inFromRightAnimation(t));
                        this.vf.setOutAnimation(AnimationHelper.outToLeftAnimation(t));
                        this.vf.showNext();}    
                    }                         
            }
            break;
            case MotionEvent.ACTION_MOVE:{

                leftView.setVisibility(View.VISIBLE);
                rightView.setVisibility(View.VISIBLE);

                float currentX = arg1.getX();     
                if(downXValue > currentX){  
                    if(currentView != view2){
                        currentView.layout((int) (currentX - downXValue),
                        currentView.getTop(),
                        (int) (currentX - downXValue) + 320,
                        currentView.getBottom()); 
                    }
                }

                if(downXValue < currentX){  
                    if(currentView != view3){
                        currentView.layout((int) (currentX - downXValue),
                        currentView.getTop(),
                        (int) (currentX - downXValue) + 320,
                        currentView.getBottom());


                    }
                }
                leftView.layout(currentView.getLeft()-320, leftView.getTop(),
                       currentView.getLeft(), leftView.getBottom());   

                rightView.layout(currentView.getRight(), rightView.getTop(), 
                        currentView.getRight() + 320, rightView.getBottom());
                }
            }

        return true;
    }

    public static class AnimationHelper {
          public static Animation inFromRightAnimation(float param) {
            Animation inFromRight = new TranslateAnimation(
            Animation.RELATIVE_TO_PARENT, +param,
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f);
            inFromRight.setDuration(250);
            inFromRight.setInterpolator(new AccelerateInterpolator());
            return inFromRight;
          }

          public static Animation outToLeftAnimation(float param) {
            Animation outtoLeft = new TranslateAnimation(
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, -param,
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f);
            outtoLeft.setDuration(250);
            outtoLeft.setInterpolator(new AccelerateInterpolator());
            return outtoLeft;
          }

          // for the next movement
          public static Animation inFromLeftAnimation(float param) {
            Animation inFromLeft = new TranslateAnimation(
            Animation.RELATIVE_TO_PARENT, -param,
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f);
            inFromLeft.setDuration(250);
            inFromLeft.setInterpolator(new AccelerateInterpolator());
            return inFromLeft;
          }

          public static Animation outToRightAnimation(float param) {
            Animation outtoRight = new TranslateAnimation(
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, +param,
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f);
            outtoRight.setDuration(250);
            outtoRight.setInterpolator(new AccelerateInterpolator());
            return outtoRight;
          }
        }

}

そのようなホームスクリーンは興味深いUI要素だと思います。

何か案は？

Answer 1

編集（2012年7月3日）：

この回答についてはまだかなりの数のビューとコメントがあるように思われるので、メモを追加する必要があると思いました。新しいSDKでは、同じ機能を使用する代わりにViewPagerを使用する必要があります。このクラスはAndroidサポートライブラリにも含まれているため、以前のAndroidデバイスで実行することもできます。

編集（2013年3月4日）：

まだまだ人が来ているので、視差効果を出すために背景を低速で動かすViewPagerをまとめました。コードはここにあります。

あなたが本当にそれをすべて手動でやりたいのなら、元の答えはここにあります...

私はあなたがここであなたが探しているものを見つけることができると思います：http ：//www.anddev.org/why_do_not_these_codes_work-t4012.html

これを別のプロジェクトで使用して、さまざまなビューのホーム画面も作成しました。これはAndroidLauncherから直接のものであり、そのスレッドをたどった後は非常にうまく機能します。

これが私のコードです...最初にソースコード

package com.matthieu.launcher;

import android.content.Context;
import android.util.Log;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewConfiguration;
import android.widget.Scroller;

public class DragableSpace extends ViewGroup {
    private Scroller mScroller;
    private VelocityTracker mVelocityTracker;

    private int mScrollX = 0;
    private int mCurrentScreen = 0;

    private float mLastMotionX;

    private static final String LOG_TAG = "DragableSpace";

    private static final int SNAP_VELOCITY = 1000;

    private final static int TOUCH_STATE_REST = 0;
    private final static int TOUCH_STATE_SCROLLING = 1;

    private int mTouchState = TOUCH_STATE_REST;

    private int mTouchSlop = 0;

    public DragableSpace(Context context) {
        super(context);
        mScroller = new Scroller(context);

        mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();

        this.setLayoutParams(new ViewGroup.LayoutParams(
                    ViewGroup.LayoutParams.WRAP_CONTENT,
                    ViewGroup.LayoutParams.FILL_PARENT));
    }

    public DragableSpace(Context context, AttributeSet attrs) {
        super(context, attrs);
        mScroller = new Scroller(context);

        mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();

        this.setLayoutParams(new ViewGroup.LayoutParams(
                    ViewGroup.LayoutParams.WRAP_CONTENT ,
                    ViewGroup.LayoutParams.FILL_PARENT));

        TypedArray a=getContext().obtainStyledAttributes(attrs,R.styleable.DragableSpace);
        mCurrentScreen = a.getInteger(R.styleable.DragableSpace_default_screen, 0);
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        /*
         * This method JUST determines whether we want to intercept the motion.
         * If we return true, onTouchEvent will be called and we do the actual
         * scrolling there.
         */

        /*
         * Shortcut the most recurring case: the user is in the dragging state
         * and he is moving his finger. We want to intercept this motion.
         */
        final int action = ev.getAction();
        if ((action == MotionEvent.ACTION_MOVE)
                && (mTouchState != TOUCH_STATE_REST)) {
            return true;
                }

        final float x = ev.getX();

        switch (action) {
            case MotionEvent.ACTION_MOVE:
                /*
                 * mIsBeingDragged == false, otherwise the shortcut would have caught it. Check
                 * whether the user has moved far enough from his original down touch.
                 */

                /*
                 * Locally do absolute value. mLastMotionX is set to the y value
                 * of the down event.
                 */
                final int xDiff = (int) Math.abs(x - mLastMotionX);

                boolean xMoved = xDiff > mTouchSlop;

                if (xMoved) {
                    // Scroll if the user moved far enough along the X axis
                    mTouchState = TOUCH_STATE_SCROLLING;
                }
                break;

            case MotionEvent.ACTION_DOWN:
                // Remember location of down touch
                mLastMotionX = x;

                /*
                 * If being flinged and user touches the screen, initiate drag;
                 * otherwise don't.  mScroller.isFinished should be false when
                 * being flinged.
                 */
                mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST : TOUCH_STATE_SCROLLING;
                break;

            case MotionEvent.ACTION_CANCEL:
            case MotionEvent.ACTION_UP:
                // Release the drag
                mTouchState = TOUCH_STATE_REST;
                break;
        }

        /*
         * The only time we want to intercept motion events is if we are in the
         * drag mode.
         */
        return mTouchState != TOUCH_STATE_REST;
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {

        if (mVelocityTracker == null) {
            mVelocityTracker = VelocityTracker.obtain();
        }
        mVelocityTracker.addMovement(event);

        final int action = event.getAction();
        final float x = event.getX();

        switch (action) {
            case MotionEvent.ACTION_DOWN:
                Log.i(LOG_TAG, "event : down");
                /*
                 * If being flinged and user touches, stop the fling. isFinished
                 * will be false if being flinged.
                 */
                if (!mScroller.isFinished()) {
                    mScroller.abortAnimation();
                }

                // Remember where the motion event started
                mLastMotionX = x;
                break;
            case MotionEvent.ACTION_MOVE:
                // Log.i(LOG_TAG,"event : move");
                // if (mTouchState == TOUCH_STATE_SCROLLING) {
                // Scroll to follow the motion event
                final int deltaX = (int) (mLastMotionX - x);
                mLastMotionX = x;

                //Log.i(LOG_TAG, "event : move, deltaX " + deltaX + ", mScrollX " + mScrollX);

                if (deltaX < 0) {
                    if (mScrollX > 0) {
                        scrollBy(Math.max(-mScrollX, deltaX), 0);
                    }
                } else if (deltaX > 0) {
                    final int availableToScroll = getChildAt(getChildCount() - 1)
                        .getRight()
                        - mScrollX - getWidth();
                    if (availableToScroll > 0) {
                        scrollBy(Math.min(availableToScroll, deltaX), 0);
                    }
                }
                // }
                break;
            case MotionEvent.ACTION_UP:
                Log.i(LOG_TAG, "event : up");
                // if (mTouchState == TOUCH_STATE_SCROLLING) {
                final VelocityTracker velocityTracker = mVelocityTracker;
                velocityTracker.computeCurrentVelocity(1000);
                int velocityX = (int) velocityTracker.getXVelocity();

                if (velocityX > SNAP_VELOCITY && mCurrentScreen > 0) {
                    // Fling hard enough to move left
                    snapToScreen(mCurrentScreen - 1);
                } else if (velocityX < -SNAP_VELOCITY
                        && mCurrentScreen < getChildCount() - 1) {
                    // Fling hard enough to move right
                    snapToScreen(mCurrentScreen + 1);
                } else {
                    snapToDestination();
                }

                if (mVelocityTracker != null) {
                    mVelocityTracker.recycle();
                    mVelocityTracker = null;
                }
                // }
                mTouchState = TOUCH_STATE_REST;
                break;
            case MotionEvent.ACTION_CANCEL:
                Log.i(LOG_TAG, "event : cancel");
                mTouchState = TOUCH_STATE_REST;
        }
        mScrollX = this.getScrollX();

        return true;
    }

    private void snapToDestination() {
        final int screenWidth = getWidth();
        final int whichScreen = (mScrollX + (screenWidth / 2)) / screenWidth;
        Log.i(LOG_TAG, "from des");
        snapToScreen(whichScreen);
    }

    public void snapToScreen(int whichScreen) {         
        Log.i(LOG_TAG, "snap To Screen " + whichScreen);
        mCurrentScreen = whichScreen;
        final int newX = whichScreen * getWidth();
        final int delta = newX - mScrollX;
        mScroller.startScroll(mScrollX, 0, delta, 0, Math.abs(delta) * 2);             
        invalidate();
    }

    public void setToScreen(int whichScreen) {
        Log.i(LOG_TAG, "set To Screen " + whichScreen);
        mCurrentScreen = whichScreen;
        final int newX = whichScreen * getWidth();
        mScroller.startScroll(newX, 0, 0, 0, 10);             
        invalidate();
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        int childLeft = 0;

        final int count = getChildCount();
        for (int i = 0; i < count; i++) {
            final View child = getChildAt(i);
            if (child.getVisibility() != View.GONE) {
                final int childWidth = child.getMeasuredWidth();
                child.layout(childLeft, 0, childLeft + childWidth, child
                        .getMeasuredHeight());
                childLeft += childWidth;
            }
        }

    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        final int width = MeasureSpec.getSize(widthMeasureSpec);
        final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        if (widthMode != MeasureSpec.EXACTLY) {
            throw new IllegalStateException("error mode.");
        }

        final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
        if (heightMode != MeasureSpec.EXACTLY) {
            throw new IllegalStateException("error mode.");
        }

        // The children are given the same width and height as the workspace
        final int count = getChildCount();
        for (int i = 0; i < count; i++) {
            getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec);
        }
        Log.i(LOG_TAG, "moving to screen "+mCurrentScreen);
        scrollTo(mCurrentScreen * width, 0);      
    }  

    @Override
    public void computeScroll() {
        if (mScroller.computeScrollOffset()) {
            mScrollX = mScroller.getCurrX();
            scrollTo(mScrollX, 0);
            postInvalidate();
        }
    }
}

そしてレイアウトファイル：

<?xml version="1.0" encoding="utf-8"?>
<com.matthieu.launcher.DragableSpace xmlns:app="http://schemas.android.com/apk/res/com.matthieu.launcher"
    xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/space"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
app:default_screen="1"
>
<include android:id="@+id/left"  layout="@layout/left_screen" />
<include android:id="@+id/center"  layout="@layout/initial_screen" />
<include android:id="@+id/right"  layout="@layout/right_screen" />
</com.matthieu.launcher.DragableSpace>

xmlファイルに追加の属性を含めることができるようにするには、これをres / values/attrs.xmlに保存します。

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="DragableSpace">
        <attr name="default_screen" format="integer"/>
    </declare-styleable>
</resources>

Answer 2

あなたはhttp://code.google.com/p/andro-views/を見るかもしれません

Answer 3

Matthieuのコードは非常に優れていますが、向きを変更した後の状態は保存されません。この問題を修正するには、DragableSpaceクラスに次のコードを追加します

 /**
     * Return the parceable instance to be saved
     */
    @Override
    protected Parcelable onSaveInstanceState() {
      final SavedState state = new SavedState(super.onSaveInstanceState());
      state.currentScreen = mCurrentScreen;
      return state;
    }


    /**
     * Restore the previous saved current screen
     */
    @Override
    protected void onRestoreInstanceState(Parcelable state) {
      SavedState savedState = (SavedState) state;
      super.onRestoreInstanceState(savedState.getSuperState());
      if (savedState.currentScreen != -1) {
        mCurrentScreen = savedState.currentScreen;
      }
    }

    // ========================= INNER CLASSES ==============================

    public interface onViewChangedEvent{      
      void onViewChange (int currentViewIndex);
    }

    /**
     * A SavedState which save and load the current screen
     */
    public static class SavedState extends BaseSavedState {
      int currentScreen = -1;

      /**
       * Internal constructor
       * 
       * @param superState
       */
      SavedState(Parcelable superState) {
        super(superState);
      }

      /**
       * Private constructor
       * 
       * @param in
       */
      private SavedState(Parcel in) {
        super(in);
        currentScreen = in.readInt();
      }

      /**
       * Save the current screen
       */
      @Override
      public void writeToParcel(Parcel out, int flags) {
        super.writeToParcel(out, flags);
        out.writeInt(currentScreen);
      }

      /**
       * Return a Parcelable creator
       */
      public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() {
        public SavedState createFromParcel(Parcel in) {
          return new SavedState(in);
        }

        public SavedState[] newArray(int size) {
          return new SavedState[size];
        }
      };
    }

私はケビンの答えからそれを取りました。