通過這個XImageView.java類，可實現單點觸摸移動，以及雙指縮放圖片功能。
使用時，只要在布局文件中引入，并在Java代碼中按照原生ImageView設置要顯示的圖片即可。
代碼如下（僅供參考）：
import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.ImageView;
public class XImageView extends ImageView {
public static Bitmap gintama;
private Matrix matrix;
private float point1_old_x, point1_old_y, point1_new_x, point1_new_y,point2_old_x, point2_old_y,point2_new_x, point2_new_y,distance_old, distance_new;
private float point_old_x, point_old_y, point_new_x, point_new_y;
private boolean isMultiTouch = false;
public XImageView(Context context, AttributeSet attrs) {
super(context, attrs);
gintama = BitmapFactory.decodeResource(getResources(),
R.drawable.ic_launcher);
matrix = new Matrix();
}
public XImageView(Context context) {
super(context);
gintama = BitmapFactory.decodeResource(getResources(),
R.drawable.ic_launcher);
matrix = new Matrix();
}
// 回調方法，用于畫控件上的圖片
@Override
protected void onDraw(Canvas canvas) {
canvas.save();
canvas.drawBitmap(gintama, matrix, null);
canvas.restore();
}
@SuppressLint("ClickableViewAccessibility")
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
// 單點移動 按下
if (event.getPointerCount() == 1) {
isMultiTouch = false;
point_old_x = event.getX();
point_old_y = event.getY();
}
break;
case MotionEvent.ACTION_UP:
// 單點移動 抬起
if (event.getPointerCount() == 1) {
isMultiTouch = false;
point_old_x = point_new_x;
point_old_y = point_new_y;
}
break;
case MotionEvent.ACTION_POINTER_UP:
// 雙點操作 抬起
if (event.getPointerCount() == 2) {
isMultiTouch = true;
point1_old_x = point1_new_x;
point1_old_y = point1_new_y;
point2_old_x = point2_new_x;
point2_old_y = point2_new_y;
}
break;
case MotionEvent.ACTION_POINTER_DOWN:
// 雙點操作 按下
if (event.getPointerCount() == 2) {
isMultiTouch = true;
point1_old_x = event.getX(0);
point1_old_y = event.getY(0);
point2_old_x = event.getX(1);
point2_old_y = event.getY(1);
distance_old = (float) Math.sqrt(((point1_old_x - point2_old_x)* (point1_old_x - point2_old_x) + (point1_old_y - point2_old_y) * (point1_old_y - point2_old_y)));
}
break;
case MotionEvent.ACTION_MOVE:
// 雙點操作 移動
if (event.getPointerCount() == 2) {
isMultiTouch = true;
point1_new_x = event.getX(0);
point1_new_y = event.getY(0);
point2_new_x = event.getX(1);\
point2_new_y = event.getY(1);
pinch();
} else {
// 單點移動 移動
if (event.getPointerCount() == 1) {
if (!isMultiTouch) {
point_new_x = event.getX();
point_new_y = event.getY();
matrix.postTranslate((point_new_x - point_old_x),(point_new_y - point_old_y));
point_old_x = point_new_x;
point_old_y = point_new_y;
invalidate();
}
}
}
break;
}
return true;
}
// 縮放圖片方法
private void pinch() {
distance_new = (float) Math.sqrt(((point1_new_x - point2_new_x)* (point1_new_x - point2_new_x) + (point1_new_y - point2_new_y) * (point1_new_y - point2_new_y)));
matrix.postScale((distance_new / distance_old),(distance_new / distance_old), this.getWidth() / 2,? this.getTop() / 2);
invalidate();
distance_old = distance_new;
}
}
