自由编码(获取网络图片)(虽然写出来了,但是感觉没有完全按照任务要求2(2)那个要求不知道怎么实现)
来源:4-3 自由编程
曾经的曾经去哪了
2018-08-28 12:33:04
package com.studio.myapplication;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.WeakReference;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private static final int DOWNLOAD_FAILED = 10086;
private static final int DOWNLOAD_SUCCESS = 74110;
private Button bt;
private ImageView iv;
private String path="https://img2.mukewang.com/5adfee7f0001cbb906000338-240-135.jpg";
private Bitmap bitmap;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
}
private void initView() {
bt= (Button) findViewById(R.id.bt);
iv= (ImageView) findViewById(R.id.iv);
bt.setOnClickListener(this);
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.bt:
GetPicThread gg=new GetPicThread();
new Thread(gg).start();
break;
}
}
private class GetPicThread implements Runnable{
private mHandler hander=new mHandler(MainActivity.this);
@Override
public void run() {
try {
URL url=new URL(path);
HttpURLConnection connection= (HttpURLConnection) url.openConnection();
connection.setConnectTimeout(10*1000);
connection.setRequestMethod("GET");
if(connection.getResponseCode()==HttpURLConnection.HTTP_OK){
InputStream inputStream=connection.getInputStream();
Bitmap bm= BitmapFactory.decodeStream(inputStream);
Message message=Message.obtain();
message.obj=bm;
message.what=bm==null?DOWNLOAD_FAILED:DOWNLOAD_SUCCESS;
hander.sendMessage(message);
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public class mHandler extends Handler{
public final WeakReference<MainActivity> mWeakReference;
public mHandler(MainActivity activity) {
this.mWeakReference = new WeakReference<>(activity);
}
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
MainActivity activity=mWeakReference.get();
switch (msg.what){
case DOWNLOAD_SUCCESS:
activity.bitmap= (Bitmap) msg.obj;
activity.iv.setImageBitmap(activity.bitmap);
break;
}
}
}
}
1回答
irista23
2018-08-28
能够使用Thread开启子线程下载图片,通过handler将图片显示到主线程,并且还是用了软引用避免内存泄漏,程序结果符合题目效果要求。任务2中是要添加一个GetPicThread类的构造方法,将path和handler通过构造方法传进来,再获取图片后封装Message,再通过handler将消息发送给UI主线程。
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