Android(安卓)handler异步更新

方法一:

package com.example.handlerdemo;import org.apache.http.HttpResponse;import org.apache.http.client.HttpClient;import org.apache.http.client.methods.HttpGet;import org.apache.http.impl.client.DefaultHttpClient;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.view.View;import android.widget.ImageView;import android.widget.Toast;public class MainActivity extends Activity {    private static final int MSG_SUCCESS = 0;// 获取图片成功的标识    private static final int MSG_FAILURE = 1;// 获取图片失败的标识    ImageView mImageView;    Handler mHandler = new Handler() {        public void handleMessage(Message msg) {            switch (msg.what) {            case MSG_SUCCESS:                mImageView.setImageBitmap((Bitmap) msg.obj);// imageview显示从网络获取到的logo                break;            case MSG_FAILURE:                Toast.makeText(getApplication(), "下载失败", Toast.LENGTH_LONG)                        .show();                break;            }        }    };protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mImageView = (ImageView) findViewById(R.id.imageView1);// 显示图片的ImageView    }    public void onClick(View v) {        switch (v.getId()) {        case R.id.button1:            mImageView.setImageBitmap(null);            new Thread(new Runnable() {                public void run() {                    HttpClient hc = new DefaultHttpClient();                    HttpGet hg = new HttpGet(                            "http://www.baidu.com/img/baidu_sylogo1.gif");// 获取百度的LOGO                    final Bitmap bm;                    try {                        HttpResponse hr = hc.execute(hg);                        bm = BitmapFactory.decodeStream(hr.getEntity()                                .getContent());                    } catch (Exception e) {                        mHandler.obtainMessage(MSG_FAILURE).sendToTarget();// 获取图片失败                        return;                    }                    mHandler.obtainMessage(MSG_SUCCESS, bm).sendToTarget();// 获取图片成功，向ui线程发送MSG_SUCCESS标识和bitmap对象                }            }).start();            break;
        }    }}

不过这个方法有个小问题老是提示会内存泄露

方法二:

package com.example.handlerdemo;import org.apache.http.HttpResponse;import org.apache.http.client.HttpClient;import org.apache.http.client.methods.HttpGet;import org.apache.http.impl.client.DefaultHttpClient;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.view.View;import android.widget.ImageView;import android.widget.Toast;public class MainActivity extends Activity {    ImageView mImageView;    Handler mHandler02 = new Handler();    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mImageView = (ImageView) findViewById(R.id.imageView1);// 显示图片的ImageView    }    public void onClick(View v) {        switch (v.getId()) {        case R.id.button2:            mImageView.setImageBitmap(null);            new Thread(new Runnable() {                public void run() {                    HttpClient hc = new DefaultHttpClient();                    HttpGet hg = new HttpGet(                            "http://www.baidu.com/img/baidu_sylogo1.gif");// 获取百度的LOGO                    try {                        HttpResponse hr = hc.execute(hg);                        final Bitmap bm = BitmapFactory.decodeStream(hr.getEntity()                                .getContent());                        mHandler02.post(new Runnable() {                            public void run() {                                mImageView.setImageBitmap(bm);// imageview显示从网络获取到的logo                            }                        });                    } catch (Exception e) {                        mHandler02.post(new Runnable() {                            public void run() {                                Toast.makeText(getApplication(), "下载失败",                                        Toast.LENGTH_LONG).show();                            }                        });                    }                                    }            }).start();            break;        default:            break;        }    }}

用方法二是不会出内存泄露的警告的

效果图:

csdn下载地址:http://download.csdn.net/detail/wenwei19861106/4868799

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