カスタムウィジェットのように使用してレイアウトに描画するビューを作成しました。しかし、最初はこのエラーが発生しました。それを乗り越えることができます。だから助けてください！
これが私のメインレイアウトです
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<com.example.SignatureView
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
これは私のSignatureViewクラスです：
public class SignatureView extends View {
private static final float STROKE_WIDTH = 5f;
/** Need to track this so the dirty region can accommodate the stroke. **/
private static final float HALF_STROKE_WIDTH = STROKE_WIDTH / 2;
private Paint paint = new Paint();
private Path path = new Path();
/**
* Optimizes painting by invalidating the smallest possible area.
*/
private float lastTouchX;
private float lastTouchY;
private final RectF dirtyRect = new RectF();
public SignatureView(Context context, AttributeSet attrs, int background) {
super(context, attrs);
setBackgroundResource(background);
paint.setAntiAlias(true);
paint.setColor(Color.BLACK);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeWidth(STROKE_WIDTH);
}
public void setColor(int color){
paint.setColor(color);
}
/**
* Erases the signature.
*/
public void clear() {
path.reset();
// Repaints the entire view.
invalidate();
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawPath(path, paint);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
float eventX = event.getX();
float eventY = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
path.moveTo(eventX, eventY);
lastTouchX = eventX;
lastTouchY = eventY;
// There is no end point yet, so don't waste cycles invalidating.
return true;
case MotionEvent.ACTION_MOVE:
case MotionEvent.ACTION_UP:
// Start tracking the dirty region.
resetDirtyRect(eventX, eventY);
// When the hardware tracks events faster than they are delivered, the
// event will contain a history of those skipped points.
int historySize = event.getHistorySize();
for (int i = 0; i < historySize; i++) {
float historicalX = event.getHistoricalX(i);
float historicalY = event.getHistoricalY(i);
expandDirtyRect(historicalX, historicalY);
path.lineTo(historicalX, historicalY);
}
// After replaying history, connect the line to the touch point.
path.lineTo(eventX, eventY);
break;
default:
// Log.("Ignored touch event: " + event.toString());
return false;
}
// Include half the stroke width to avoid clipping.
invalidate(
(int) (dirtyRect.left - HALF_STROKE_WIDTH),
(int) (dirtyRect.top - HALF_STROKE_WIDTH),
(int) (dirtyRect.right + HALF_STROKE_WIDTH),
(int) (dirtyRect.bottom + HALF_STROKE_WIDTH));
lastTouchX = eventX;
lastTouchY = eventY;
return true;
}
/**
* Called when replaying history to ensure the dirty region includes all
* points.
*/
private void expandDirtyRect(float historicalX, float historicalY) {
if (historicalX < dirtyRect.left) {
dirtyRect.left = historicalX;
} else if (historicalX > dirtyRect.right) {
dirtyRect.right = historicalX;
}
if (historicalY < dirtyRect.top) {
dirtyRect.top = historicalY;
} else if (historicalY > dirtyRect.bottom) {
dirtyRect.bottom = historicalY;
}
}
/**
* Resets the dirty region when the motion event occurs.
*/
private void resetDirtyRect(float eventX, float eventY) {
// The lastTouchX and lastTouchY were set when the ACTION_DOWN
// motion event occurred.
dirtyRect.left = Math.min(lastTouchX, eventX);
dirtyRect.right = Math.max(lastTouchX, eventX);
dirtyRect.top = Math.min(lastTouchY, eventY);
dirtyRect.bottom = Math.max(lastTouchY, eventY);
}
}
これが私のメインのDrawクラスにあるものです。
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
そして最後に、これは私がlogCatで取得しているものです
02-19 17:41:51.708: E/AndroidRuntime(7530): FATAL EXCEPTION: main
02-19 17:41:51.708: E/AndroidRuntime(7530): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example/com.example.Draw}: android.view.InflateException: Binary XML file line #6: Error inflating class com.example.SignatureView
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1662)
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1678)
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.app.ActivityThread.access$1500(ActivityThread.java:118)
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:932)
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.os.Handler.dispatchMessage(Handler.java:99)
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.os.Looper.loop(Looper.java:130)
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.app.ActivityThread.main(ActivityThread.java:3698)
02-19 17:41:51.708: E/AndroidRuntime(7530): at java.lang.reflect.Method.invokeNative(Native Method)
02-19 17:41:51.708: E/AndroidRuntime(7530): at java.lang.reflect.Method.invoke(Method.java:507)
02-19 17:41:51.708: E/AndroidRuntime(7530): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:875)
02-19 17:41:51.708: E/AndroidRuntime(7530): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:633)
02-19 17:41:51.708: E/AndroidRuntime(7530): at dalvik.system.NativeStart.main(Native Method)
02-19 17:41:51.708: E/AndroidRuntime(7530): Caused by: android.view.InflateException: Binary XML file line #6: Error inflating class com.example.SignatureView
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.view.LayoutInflater.createView(LayoutInflater.java:508)
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:570)
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.view.LayoutInflater.rInflate(LayoutInflater.java:623)
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.view.LayoutInflater.inflate(LayoutInflater.java:408)
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.view.LayoutInflater.inflate(LayoutInflater.java:320)
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.view.LayoutInflater.inflate(LayoutInflater.java:276)
02-19 17:41:51.708: E/AndroidRuntime(7530): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:207)
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.app.Activity.setContentView(Activity.java:1657)
02-19 17:41:51.708: E/AndroidRuntime(7530): at com.example.Draw.onCreate(Draw.java:13)
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1626)
02-19 17:41:51.708: E/AndroidRuntime(7530): ... 11 more
02-19 17:41:51.708: E/AndroidRuntime(7530): Caused by: java.lang.NoSuchMethodException: SignatureView(Context,AttributeSet)
02-19 17:41:51.708: E/AndroidRuntime(7530): at java.lang.Class.getMatchingConstructor(Class.java:643)
02-19 17:41:51.708: E/AndroidRuntime(7530): at java.lang.Class.getConstructor(Class.java:472)
02-19 17:41:51.708: E/AndroidRuntime(7530): at android.view.LayoutInflater.createView(LayoutInflater.java:480)
02-19 17:41:51.708: E/AndroidRuntime(7530): ... 21 more