自定义ImageView

package com.example.dell.myapplication; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Handler; import android.os.Message; import android.util.AttributeSet; import android.util.DisplayMetrics; import android.util.Log; import android.view.ViewGroup; import android.widget.ImageView; import android.widget.Toast; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.URL; public class MyImageView extends ImageView { private String imagePath; //是否启用缓存 public boolean isUseCache = false; public static final int GET_DATA_SUCCESS = 1; public static final int NETWORK_ERROR = 2; public static final int SERVER_ERROR = 3; //子线程不能操作UI，通过Handler设置图片 private Handler handler = new Handler() { @Override public void handleMessage(Message msg) { switch (msg.what) { case GET_DATA_SUCCESS: Bitmap bitmap = (Bitmap) msg.obj; setImageBitmap(bitmap); break; case NETWORK_ERROR: Toast.makeText(getContext(), "网络连接失败", Toast.LENGTH_SHORT).show(); break; case SERVER_ERROR: Toast.makeText(getContext(), "服务器发生错误", Toast.LENGTH_SHORT).show(); break; } } }; public MyImageView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); } public MyImageView(Context context) { super(context); } public MyImageView(Context context, AttributeSet attrs) { super(context, attrs); } //设置网络图片 public void setImageURL(String path) { imagePath = path; if (isUseCache){ useCacheImage(); }else { useNetWorkImage(); } } //使用网络图片显示 public void useNetWorkImage(){ //开启一个线程用于联网 new Thread() { @Override public void run() { try { //把传过来的路径转成URL URL url = new URL(imagePath); //获取连接 HttpURLConnection connection = (HttpURLConnection) url.openConnection(); //使用GET方法访问网络 connection.setRequestMethod("GET"); //超时时间为10秒 connection.setConnectTimeout(10000); //获取返回码 int code = connection.getResponseCode(); if (code == 200) { Bitmap bitmap; //获取网络输入流 InputStream inputStream = connection.getInputStream(); //判断是否使用缓存图片 if (isUseCache){ //因为InputStream要使用两次，但是使用一次就无效了，所以需要复制两个 ByteArrayOutputStream baos = new ByteArrayOutputStream(); try { byte[] buffer = new byte[1024]; int len; while ((len = inputStream.read(buffer)) > -1) { baos.write(buffer, 0, len); } baos.flush(); } catch (IOException e) { e.printStackTrace(); } //复制新的输入流 InputStream is = new ByteArrayInputStream(baos.toByteArray()); InputStream is2 = new ByteArrayInputStream(baos.toByteArray()); //调用压缩方法显示图片 bitmap = getCompressBitmap(is); //调用缓存图片方法 cacheImage(is2); }else { //调用压缩方法 bitmap = getCompressBitmap(inputStream); } //利用Message把图片发给Handler Message msg = Message.obtain(); msg.obj = bitmap; msg.what = GET_DATA_SUCCESS; handler.sendMessage(msg); inputStream.close(); } else { //服务启发生错误 handler.sendEmptyMessage(SERVER_ERROR); } } catch (IOException e) { e.printStackTrace(); //网络连接错误 handler.sendEmptyMessage(NETWORK_ERROR); } } }.start(); } //使用缓存图片 public void useCacheImage() { //创建路径一样的文件 File file = new File(getContext().getCacheDir(), getURLPath()); //判断文件是否存在 if (file != null && file.length() > 0) { //使用本地图片 try { InputStream inputStream = new FileInputStream(file); //调用压缩方法显示图片 Bitmap bitmap = getCompressBitmap(inputStream); //利用Message把图片发给Handler Message msg = Message.obtain(); msg.obj = bitmap; msg.what = GET_DATA_SUCCESS; handler.sendMessage(msg); Log.e("MyImageView","使用缓存图片"); } catch (FileNotFoundException e) { e.printStackTrace(); } }else { //使用网络图片 useNetWorkImage(); Log.e("MyImageView","使用网络图片"); } } /** * 缓存网络的图片 * @param inputStream 网络的输入流 */ public void cacheImage(InputStream inputStream) { try { File file = new File(getContext().getCacheDir(), getURLPath()); FileOutputStream fos = new FileOutputStream(file); int len; byte[] buffer = new byte[1024]; while ((len = inputStream.read(buffer)) != -1) { fos.write(buffer, 0, len); } fos.close(); Log.e("MyImageView","缓存成功"); } catch (IOException e) { e.printStackTrace(); Log.e("MyImageView","缓存失败"); } } /** * 根据网址生成一个文件名 * @return 文件名 */ public String getURLPath() { StringBuilder urlStr2 = new StringBuilder(); String[] strings = imagePath.split("\\/"); for (String string : strings) { urlStr2.append(string); } Log.e("MyImageView","文件名："+urlStr2.toString()); return urlStr2.toString(); } /** * 根据输入流返回一个压缩的图片 * * @param input 图片的输入流 * @return 压缩的图片 */ public Bitmap getCompressBitmap(InputStream input) { //因为InputStream要使用两次，但是使用一次就无效了，所以需要复制两个 ByteArrayOutputStream baos =