调节图片大小且移动图片（非自定义控件）-优快云博客

本文链接：https://blog.youkuaiyun.com/alone_egg/article/details/131900988

该代码示例展示了在Android中如何实现对ImageView的手势操作，包括拖动滑动和pinch-to-zoom缩放功能。使用RelativeLayout作为根布局，包含一个ImageView和一个Switch。当Switch开启时，ImageView启用缩放手势检测；关闭时，启用滑动功能。滑动操作中，记录了初始位置并在ACTION_MOVE时更新视图位置。缩放操作通过ScaleGestureDetector实现，限制缩放范围在0.1到5.0之间。

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<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

   <ImageView
       android:id="@+id/iv_1"
       android:layout_width="150dp"
       android:layout_height="150dp"
       android:layout_centerHorizontal="true"
       android:layout_centerVertical="true"
       android:src="@drawable/demo1"/>

   <Switch
       android:id="@+id/switchButton"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:layout_below="@+id/iv_1"
       android:layout_marginTop="40dp"
       android:layout_centerHorizontal="true"/>

</RelativeLayout>

public class MainActivity extends AppCompatActivity {

    private ImageView iv_1;
    private int screenHeightHalf;

    private int originalLeft, originalTop, originalRight, originalBottom;
    private Switch switchButton;
    private ScaleGestureDetector scaleGestureDetector;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        screenHeightHalf = getScreenHeightHalf(MainActivity.this);

        switchButton = findViewById(R.id.switchButton);

        iv_1 = (ImageView) findViewById(R.id.iv_1);

        scaleGestureDetector = new ScaleGestureDetector(this, new ScaleListener());

        iv_1.setOnTouchListener(touchListener);


        switchButton.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if (isChecked){
                    iv_1.setOnTouchListener(touchListener2);

                }else {
                    iv_1.setOnTouchListener(touchListener);

                }
            }
        });

    }



    private View.OnTouchListener touchListener2=new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            scaleGestureDetector.onTouchEvent(event);
            return true;
        }
    };



    private View.OnTouchListener touchListener = new View.OnTouchListener() {
        private int lastX, lastY;

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            switch (event.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    lastX = (int) event.getRawX();
                    lastY = (int) event.getRawY();
                    originalLeft = v.getLeft();
                    originalTop = v.getTop();
                    originalRight = v.getRight();
                    originalBottom = v.getBottom();
                    break;
                case MotionEvent.ACTION_MOVE:
                    //测试控件移动的位置
                    int top = v.getTop();
                    int screenHeight = screenHeightHalf * 2;
                    Log.d("TAG", "ImageView Top: " + top + ", Screen Height: " + screenHeight);

                    moveView(v, event.getRawX() - lastX, event.getRawY() - lastY);
                    lastX = (int) event.getRawX();
                    lastY = (int) event.getRawY();
                    break;
                case MotionEvent.ACTION_UP:
                    switch (v.getId()){
                        case R.id.iv_1:
                            Toast.makeText(MainActivity.this, "1", Toast.LENGTH_SHORT).show();
                            break;


                    }
                    // 处理抬起事件
                    /*if (v.getTop()<500) {
                        // 返回原始位置
                        //TODO
                        Toast.makeText(MainActivity.this, "超过1/2屏幕高度", Toast.LENGTH_SHORT).show();
                    }else {
                        v.layout(originalLeft, originalTop, originalRight, originalBottom);
                    }*/

                    break;
            }
            return true;
        }
    };

    private void moveView(View view, float dx, float dy) {
        int left = view.getLeft() + (int) dx;
        int top = view.getTop() + (int) dy;
        int right = view.getRight() + (int) dx;
        int bottom = view.getBottom() + (int) dy;
        view.layout(left, top, right, bottom);
    }






    public int getScreenHeightHalf(Context context) {
        DisplayMetrics displayMetrics = context.getResources().getDisplayMetrics();
        return displayMetrics.heightPixels / 2;
    }


    private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
        private float scaleFactor = 1.0f;

        @Override
        public boolean onScale(ScaleGestureDetector detector) {
            scaleFactor *= detector.getScaleFactor();
            scaleFactor = Math.max(0.1f, Math.min(scaleFactor, 5.0f));

            iv_1.setScaleX(scaleFactor);
            iv_1.setScaleY(scaleFactor);

            return true;
        }
    }


}

参考了之前的一篇手势滑动的博客