Android通过网络URL获取图片并显示

1.布局文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="${relativePackage}.${activityClass}"
android:orientation="vertical" >

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />

<ImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>

<Button
android:id="@+id/button"
android:layout_width="300dp"
android:layout_height="70dp"
android:layout_gravity="center_horizontal"
android:text="获取网络图片"/>
</LinearLayout>

2.在AndroidManifest.xml添加可以访问网络的权限

<uses-permission android:name="android.permission.INTERNET" />

3.主要代码

package com.example.pic;

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

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.StrictMode;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;

public class MainActivity extends Activity {

private Button btn;
private ImageView imageview;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

btn = (Button) this.findViewById(R.id.button);
imageview = (ImageView) this.findViewById(R.id.imageView);

StrictMode.setThreadPolicy(new
StrictMode.ThreadPolicy.Builder().detectDiskReads().detectDiskWrites().detectNetwork().penaltyLog().build());
StrictMode.setVmPolicy(
new StrictMode.VmPolicy.Builder().detectLeakedSqlLiteObjects().detectLeakedClosableObjects().penaltyLog().penaltyDeath().build());

btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
btn.setEnabled(false);
String strURL = "http://192.168.31.184:8011/main.png";
try {
Bitmap bitmap = getBitmap(strURL);
imageview.setImageBitmap(bitmap);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}

public Bitmap getBitmap(String path) throws IOException {
try {
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5000);
conn.setRequestMethod("GET");
if (conn.getResponseCode() == 200) {
InputStream inputStream = conn.getInputStream();
Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
return bitmap;
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}

}

下面这一段代码很重要

StrictMode.setThreadPolicy(new
StrictMode.ThreadPolicy.Builder().detectDiskReads().detectDiskWrites().detectNetwork().penaltyLog().build());
StrictMode.setVmPolicy(
new StrictMode.VmPolicy.Builder().detectLeakedSqlLiteObjects().detectLeakedClosableObjects().penaltyLog().penaltyDeath().build());

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