今天刚发了一篇关于ImageView的缩放和拖拽的博客，然后我想了下，将他自定义下,方便我们来复用这个imageView，效果我就不多说了，http://blog.csdn.net/xiaanming/article/details/8827257就是这个效果，我只是把他抽出来自定义了下，代码还是贴上吧，我也将demo上传一下，有疑问大家指出来，大家共同学习，共同进步，呵呵
package com.example.myimageview;import android.content.Context;import android.graphics.Bitmap;import android.graphics.Matrix;import android.graphics.PointF;import android.graphics.RectF;import android.graphics.drawable.BitmapDrawable;import android.util.AttributeSet;import android.util.DisplayMetrics;import android.util.FloatMath;import android.view.MotionEvent;import android.view.View;import android.widget.ImageView;public class MyImageView extends ImageView{ Matrix matrix = new Matrix(); Matrix savedMatrix = new Matrix(); /**位图对象*/ private Bitmap bitmap = null; /** 屏幕的分辨率*/ private DisplayMetrics dm; /** 最小缩放比例*/ float minScaleR = 1.0f; /** 最大缩放比例*/ static final float MAX_SCALE = 15f; /** 初始状态*/ static final int NONE = 0; /** 拖动*/ static final int DRAG = 1; /** 缩放*/ static final int ZOOM = 2; /** 当前模式*/ int mode = NONE; /** 存储float类型的x，y值，就是你点下的坐标的X和Y*/ PointF prev = new PointF(); PointF mid = new PointF(); float dist = 1f; public MyImageView(Context context) { super(context); setupView(); } public MyImageView(Context context, AttributeSet attrs) { super(context, attrs); setupView(); } public void setupView(){ Context context = getContext(); //获取屏幕分辨率,需要根据分辨率来使用图片居中 dm = context.getResources().getDisplayMetrics(); //根据MyImageView来获取bitmap对象 BitmapDrawable bd = (BitmapDrawable)this.getDrawable(); if(bd != null){ bitmap = bd.getBitmap(); } //设置ScaleType为ScaleType.MATRIX，这一步很重要 this.setScaleType(ScaleType.MATRIX); this.setImageBitmap(bitmap); //bitmap为空就不调用center函数 if(bitmap != null){ center(true, true); } this.setImageMatrix(matrix); this.setOnTouchListener(new OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { switch (event.getAction() & MotionEvent.ACTION_MASK) { // 主点按下 case MotionEvent.ACTION_DOWN: savedMatrix.set(matrix); prev.set(event.getX(), event.getY()); mode = DRAG; break; // 副点按下 case MotionEvent.ACTION_POINTER_DOWN: dist = spacing(event); // 如果连续两点距离大于10，则判定为多点模式 if (spacing(event) > 10f) { savedMatrix.set(matrix); midPoint(mid, event); mode = ZOOM; } break; case MotionEvent.ACTION_UP:{ break; } case MotionEvent.ACTION_POINTER_UP: mode = NONE; //savedMatrix.set(matrix); break; case MotionEvent.ACTION_MOVE: if (mode == DRAG) { matrix.set(savedMatrix); matrix.postTranslate(event.getX() - prev.x, event.getY() - prev.y); } else if (mode == ZOOM) { float newDist = spacing(event); if (newDist > 10f) { matrix.set(savedMatrix); float tScale = newDist / dist; matrix.postScale(tScale, tScale, mid.x, mid.y); } } break; } MyImageView.this.setImageMatrix(matrix); CheckView(); return true; } }); } /** * 横向、纵向居中 */ protected void center(boolean horizontal, boolean vertical) { Matrix m = new Matrix(); m.set(matrix); RectF rect = new RectF(0, 0, bitmap.getWidth(), bitmap.getHeight()); m.mapRect(rect); float height = rect.height(); float width = rect.width(); float deltaX = 0, deltaY = 0; if (vertical) { // 图片小于屏幕大小，则居中显示。大于屏幕，上方留空则往上移，下方留空则往下移 int screenHeight = dm.heightPixels; if (height < screenHeight) { deltaY = (screenHeight - height) / 2 - rect.top; } else if (rect.top > 0) { deltaY = -rect.top; } else if (rect.bottom < screenHeight) { deltaY = this.getHeight() - rect.bottom; } } if (horizontal) { int screenWidth = dm.widthPixels; if (width < screenWidth) { deltaX = (screenWidth - width) / 2 - rect.left; } else if (rect.left > 0) { deltaX = -rect.left; } else if (rect.right < screenWidth) { deltaX = screenWidth - rect.right; } } matrix.postTranslate(deltaX, deltaY); } /** * 限制最大最小缩放比例，自动居中 */ private void CheckView() { float p[] = new float[9]; matrix.getValues(p); if (mode == ZOOM) { if (p[0] < minScaleR) { //Log.d("", "当前缩放级别:"+p[0]+",最小缩放级别:"+minScaleR); matrix.setScale(minScaleR, minScaleR); } if (p[0] > MAX_SCALE) { //Log.d("", "当前缩放级别:"+p[0]+",最大缩放级别:"+MAX_SCALE); matrix.set(savedMatrix); } } center(true, true); } /** * 两点的距离 */ private float spacing(MotionEvent event) { float x = event.getX(0) - event.getX(1); float y = event.getY(0) - event.getY(1); return FloatMath.sqrt(x * x + y * y); } /** * 两点的中点 */ private void midPoint(PointF point, MotionEvent event) { float x = event.getX(0) + event.getX(1); float y = event.getY(0) + event.getY(1); point.set(x / 2, y / 2); }}<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="fill_parent" android:layout_height="fill_parent" > <com.example.myimageview.MyImageView android:id="@+id/imageview" android:layout_width="fill_parent" android:layout_height="fill_parent" android:src="@drawable/item" > </com.example.myimageview.MyImageView></RelativeLayout>新建一个MainActivity咯，
package com.example.myimageview;import android.app.Activity;import android.os.Bundle;public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); MyImageView myImageView = (MyImageView)findViewById(R.id.imageview); myImageView.setImageDrawable(getResources().getDrawable(R.drawable.item1)); }}再分享一下我老师大神的人工智能教程吧。零基础！通俗易懂！风趣幽默！还带黄段子！希望你也加入到我们人工智能的队伍中来！https://blog.csdn.net/jiangjunshow