网络图片查看器

activity:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/LinearLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<ImageView
android:id="@+id/ivimg"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_weight="1" />

<EditText
android:id="@+id/eturl"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:text="http://pic70.nipic.com/file/20150617/21266988_113316974000_2.jpg" />

<Button
android:id="@+id/btn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="btn"
android:layout_gravity="center"
android:text="点击" />

</LinearLayout>

MainActivity：

package com.example.image;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.text.TextUtils;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;

@SuppressLint("HandlerLeak") 
public class MainActivity extends Activity {
private EditText eturl;
private ImageView ivimg;
public static final int SHOWIMAGE=1;
public static final int SHOWFAIL=0;
// Handler 处理事件
private Handler handler=new Handler(){
public void handleMessage(android.os.Message msg) {
switch (msg.what) {
case SHOWIMAGE:
Bitmap bitmap=(Bitmap) msg.obj;
ivimg.setImageBitmap(bitmap);
break;

case SHOWFAIL:
ivimg.setImageResource(R.drawable.keai);
Toast.makeText(MainActivity.this, "显示图片失败", Toast.LENGTH_LONG).show();
break;

default:
break;
}
};
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initViews();
ivimg.setImageResource(R.drawable.keai);
}
// 查找的ID
private void initViews() {
eturl=(EditText) findViewById(R.id.eturl);
ivimg=(ImageView) findViewById(R.id.ivimg);
}

// 按钮点击事件
public void btn(View view){
final String imageUrl=eturl.getText().toString();
if(TextUtils.isEmpty(imageUrl)){
Toast.makeText(this, "图片路径不能为空", Toast.LENGTH_LONG).show();
}else{
new Thread(){
public void run() {
try {
URL url=new URL(imageUrl);
HttpURLConnection httpURLConnection=(HttpURLConnection) url.openConnection();
httpURLConnection.setRequestMethod("GET");
httpURLConnection.setConnectTimeout(5000);
int responseCode=httpURLConnection.getResponseCode();
if(responseCode==200){
InputStream inputStream=httpURLConnection.getInputStream();
Bitmap bitmap=BitmapFactory.decodeStream(inputStream);
Message message=new Message();
message.what=SHOWIMAGE;
message.obj=bitmap;
//ivImage.setImageBitmap(bitmap);
handler.sendMessage(message);
}else{
Message message=new Message();
message.what=SHOWFAIL;
handler.sendMessage(message);
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}.start();
}
}

}