このコードを使用して、テキストビューの行数を確認します。
MainActivity.java
import android.app.Activity;
import android.os.Bundle;
import android.view.ViewTreeObserver;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.widget.TextView;
public class MainActivity extends Activity {
TextView textView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = (TextView) findViewById(R.id.textView1);
int totalLines = textView.getLineCount();
ViewTreeObserver vto = this.textView.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
public void onGlobalLayout() {
ViewTreeObserver obs = textView.getViewTreeObserver();
obs.removeGlobalOnLayoutListener(this);
System.out.println("Line Count is : " + textView.getLineCount());
}
});
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<TextView
android:id="@+id/textView1"
android:layout_width="300dp"
android:layout_height="500dp"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="I have a full-screen TextView holding a long Spanned that requires scrolling. The TextView's getLineCount() gives me the total number of lines used for the entire block of text but I'd like to know how many lines of text are currently visible on the screen. "
android:textAppearance="?android:attr/textAppearanceLarge" />
</RelativeLayout>
スクロール付きの Textview を使用していて、画面に表示されている行数 (合計行数ではない) を知る必要がある場合、
int height = myTextView.getHeight();
int scrollY = myTextView.getScrollY();
Layout layout = myTextView.getLayout();
int firstVisibleLineNumber = layout.getLineForVertical(scrollY);
int lastVisibleLineNumber = layout.getLineForVertical(scrollY+height);