Android 解决大图片OOM问题

package com.dy; import java.io.File; import java.io.FileNotFoundException; import java.util.ArrayList; import tool.BitmapTool; import tool.ScreenTool; import tool.ScreenTool.Screen; import com.dy.R; import android.app.Activity; import android.content.Intent; import android.graphics.Bitmap; import android.graphics.Matrix; import android.graphics.PointF; import android.os.Bundle; import android.util.FloatMath; import android.util.Log; import android.view.GestureDetector; import android.view.GestureDetector.OnGestureListener; import android.view.MotionEvent; import android.view.View; import android.view.View.OnTouchListener; import android.view.animation.TranslateAnimation; import android.widget.ImageView; import android.widget.Toast; public class PictureActivity extends Activity implements OnTouchListener, OnGestureListener { private ImageView pictureImageView; // pictureImageView的宽和高 private int pictureImageViewWidth = 0; private int pictureImageViewHeight = 0; // 屏幕宽和高 private Screen screen; private int screenWidth; private int screenHeight; // 文件地址列表 private ArrayList<String> filePath; // 在文件地址列表中的当前位置 private int position; // 用于设置pictureImageView的矩阵 private Matrix setMatrix = new Matrix(); // 暂存之前的矩阵 private Matrix savedMatrix = new Matrix(); // 记录加载后原始的矩阵 private Matrix initialMatrix = new Matrix(); private GestureDetector gestureDetector; // 记录是否返回手势指令 private boolean isReturnGesture = true; // 手势模式 private static final int NONE = 0; private static final int DRAG = 1; private static final int ZOOM = 2; private int mode = NONE; // 手势的起点和中点 private PointF start = new PointF(); private PointF mid = new PointF(); // 两个手指拉开前的距离 private float oldDistance = 1f; // 加载的图片 private Bitmap bitmap; // 图片加载压缩后的宽和高 private int bitmapWidth; private int bitmapHeight; // 图片放在控件后的宽和高 private int bitmapRealWidth = 0; private int bitmapRealHeight = 0; // 图片共放缩的倍数 private float scaleTotalTimes = 1f; // 存储当前放缩的倍数 private float scaleNowTimes; // 存放上次放缩的倍数 private float scaleLastTimes = 0f; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.picture); // 设置imageView的配置 this.pictureImageView = (ImageView) this .findViewById(R.id.pictureImageView); pictureImageView.setLongClickable(true); pictureImageView.setOnTouchListener(this); Intent intent = this.getIntent(); Bundle bundle = intent.getExtras(); filePath = bundle.getStringArrayList("filePath"); position = bundle.getInt("index"); // 调用工具类得到屏幕的大小 screen = ScreenTool.getScreenPix(this); this.screenWidth = screen.widthPixels; this.screenHeight = screen.heightPixels; // 设置手势类 gestureDetector = new GestureDetector(this); gestureDetector.setIsLongpressEnabled(true); // 加载图片到pictureImageView this.LoadBitmap(); } // 触摸屏幕 public boolean onTouch(View v, MotionEvent event) { ImageView view = (ImageView) v; float scaleTemp = 1f; switch (event.getAction() & MotionEvent.ACTION_MASK) { // 点击屏幕 case MotionEvent.ACTION_DOWN: setMatrix.set(view.getImageMatrix()); // 暂存原来的矩阵 savedMatrix.set(setMatrix); start.set(event.getX(), event.getY()); // 拖放模式 mode = DRAG; break; // 多点触摸 case MotionEvent.ACTION_POINTER_DOWN: // 计算两指距离 oldDistance = spacing(event); if (oldDistance > 10f) { savedMatrix.set(setMatrix); // 取得两指的中点 midPoint(mid, event); // 缩放模式 mode = ZOOM; } break; // 屏幕上所有手指放开时触发 case MotionEvent.ACTION_UP: // 用户是否缩放 if (this.scaleNowTimes != 0 && Math.abs(this.scaleLastTimes - this.scaleNowTimes) > 0.0001) { // 更新总缩放倍数 this.scaleTotalTimes = this.scaleTotalTimes * this.scaleNowTimes; // 保存为上次缩放倍数 this.scaleLastTimes = this.scaleNowTimes; } // 计算边界，返回边界极限值 float moveResult[] = this.computerLimit(this.scaleTotalTimes, event.getX()); // 用于缩小超过极限，重新设置矩阵 if (moveResult == null) { setMatrix.set(initialMatrix); this.isReturnGesture = true; } else { // 需要下一张图 if (moveResult[2] == 1f) { this.isReturnGesture = true; } // 矫正图片位置 setMatrix.postTranslate(moveResult[0], moveResult[1]); } break; // 屏幕上有多只手指时（大于一只），当其中一只放开时触发 case MotionEvent.ACTION_POINTER_UP: mode = NONE; break; case MotionEvent.ACTION_MOVE: if (mode == DRAG) { // 读取原来的矩阵 setMatrix.set(savedMatrix); setMatrix.postTranslate(event.getX() - start.x, event.getY() - start.y); } else if (mode == ZOOM) { // 取得划完之后两个手指的距离 float newDist = spacing(event); if (newDist > 10f) { // 读取原来的矩阵 setMatrix.set(savedMatrix); // 计算缩放比率 scaleTemp = newDist / oldDistance; // 记录缩放比率 this.scaleNowTimes = scaleTemp; setMatrix.postScale(scaleTemp, scaleTemp, mid.x, mid.y); // 不需要下一张图 this.isReturnGesture = false; } } break; } view.setImageMatrix(setMatrix); // 判断是否需要下一张 if (this.isReturnGesture) return gestureDetector.onTouchEvent(event); else return true; } // 两个手指之间的距离 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); } // 取得两个手指的中点 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); } public boolean onDown(MotionEvent e) { return false; } // 滑动下一张图 public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { float x = e2.getX() - e1.getX(); float y = e2.getY() - e1.getY(); // 限制必须得划过屏幕的1/3才能算划过 float x_limit = screen.widthPixels / 3; float x_abs = Math.abs(x); float y_abs = Math.abs(y); if (x_abs >= y_abs) { if (x > x_limit || x < -x_limit) { if (x > 0) { // 向右划 position--; while (position >= 0 && !isFile(filePath.get(position))) { position--; } if (position >= 0) { // 添加滑动的动画 TranslateAnimation trans = new TranslateAnimation(-x, 0, -y, 0); trans.setDuration(300); pictureImageView.startAnimation(trans); // 加载图片 this.LoadBitmap(); } else { show("到顶了"); position++; while (!isFile(filePath.get(position))) { position++; } } } else if (x <= 0) { // 向左划 position++; while (position < filePath.size() && !isFile(filePath.get(position))) { position++; } if (position < filePath.size()) { // 添加滑动的动画 TranslateAnimation trans = new TranslateAnimation(-x, 0, -y, 0); trans.setDuration(500); pictureImageView.startAnimation(trans); // 加载图片 this.LoadBitmap(); } else { show("到底了"); position--; while (!isFile(filePath.get(position))) { position--; } } } } } return true; } // 初始化图片的矩阵 private void initialMatrix() { Matrix tempMatrix = this.pictureImageView.getImageMatrix(); tempMatrix.reset(); // 图片的真实宽和高 int imageWidth = this.bitmapWidth; int imageHeight = this.bitmapHeight; float temp = 1f; float moveHeight = 0f; float moveWidth = 0f; // 图片宽大于高 if