開放的FileDialog

Question

我在Android的初學者，我試圖發展設置壁紙App.After點擊圖像第二活動將open.Here是我的代碼：

的manifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="com.example.myfirstapplication" 
    android:versionCode="1" 
    android:versionName="1.0" > 
    <uses-sdk 
     android:minSdkVersion="7" 
     android:targetSdkVersion="15" /> 

    <application 
     android:icon="@drawable/ic_launcher" 
     android:label="@string/app_name" 
     android:theme="@style/AppTheme" > 
     <activity 
      android:name=".MainActivity" 
      android:label="@string/title_activity_main" > 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 

       <category android:name="android.intent.category.LAUNCHER" /> 
      </intent-filter> 
     </activity> 
     <activity android:name=".secondActivity" 
        android:label="@string/app_name"> 
     </activity> 
    </application> 

</manifest> 

activity_main.xml中

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="wrap_content" 
    android:layout_height="fill_parent" 
    android:orientation="vertical" 
    android:paddingLeft="8dp" 
    android:paddingRight="8dp" > 

    <ImageView 
     android:id="@+id/imageView1" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:src="@android:drawable/btn_star_big_on" 
     android:clickable="true" 
     android:onClick="imageClick" /> 

    <TextView 
     android:id="@android:id/empty" 
     android:layout_width="150dp" 
     android:layout_height="wrap_content" 
     android:text="Wallpaper" /> 
</LinearLayout> 

main.xml中

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="wrap_content" 
    android:layout_height="fill_parent" 
    android:orientation="vertical" 
    android:paddingLeft="8dp" 
    android:paddingRight="8dp" > 

    <Button 
     android:id="@+id/set" 
     android:layout_width="298dp" 
     android:layout_height="70dp" 
     android:text="Set Wallpaper" /> 


    <Button 
     android:id="@+id/hoti" 
     android:layout_width="fill_parent" 
     android:layout_height="193dp" 
     android:text="HOTI" /> 

    <Button 
     android:id="@+id/smb" 
     android:layout_width="298dp" 
     android:layout_height="70dp" 
     android:text="See More" /> 
    <Button 
     android:id="@+id/quit" 
     android:layout_width="298dp" 
     android:layout_height="70dp" 
     android:text="Quit" /> 
</LinearLayout> 

MainActivity.java

package com.example.myfirstapplication; 

import android.app.Activity; 
import android.content.Intent; 
import android.os.Bundle; 
import android.view.View; 

public class MainActivity extends Activity { 

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


public void imageClick(View v){ 

    //Create an intent to start the new activity. 
     // Our intention is to start secondActivity 
    Intent intent = new Intent(); 
    intent.setClass(this,secondActivity.class); 
    startActivity(intent); 
    } 
} 

secondActivity.java

package com.example.myfirstapplication; 

import android.app.Activity; 
import android.graphics.Bitmap; 
import android.os.Bundle; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 


public class secondActivity extends Activity { 
    Bitmap bitmap; 
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

    // Set the layout for this activity 
     setContentView(R.layout.main); 


     Button btn1 = (Button) findViewById(R.id.quit); 
     btn1.setOnClickListener(new OnClickListener() { 

      public void onClick(View v) { 
       // TODO Auto-generated method stub 
       finish(); 
       System.exit(0); 
      } 
     }); 
     } 

} 

點擊設置壁紙按鈕後的文件選擇應打開從中我可以選擇圖像，也是我可以看到圖像的預覽和能將其設置爲壁紙。請幫助我。 我也想在點擊「查看更多」按鈕後打開一個彈出窗口。

Answer 1

showFileChooser（）方法會爲你做這個。 希望你得到你的要求。

private void showFileChooser() { 
      Intent intent = new Intent(Intent.ACTION_GET_CONTENT); 
      intent.setType("*/*"); 
      intent.addCategory(Intent.CATEGORY_OPENABLE); 

      try { 
       startActivityForResult(
         Intent.createChooser(intent, "Select a Image"), FILE_SELECT_CODE); 
      } catch (android.content.ActivityNotFoundException ex) { 
       Toast.makeText(this, "Please install a File Manager.",Toast.LENGTH_SHORT).show(); 
      } 
     } 

     @Override 
     protected void onActivityResult(int requestCode, int resultCode, Intent data) { 
      super.onActivityResult(requestCode, resultCode, data); 
      switch (requestCode) { 
       case FILE_SELECT_CODE:  
       if (resultCode == RESULT_OK) { 

        Uri uri = data.getData(); 
        String path = getRealPathFromURI(uri); 
        File imgFile = new File(path); 
        if(imgFile.exists()) 
        { 
         myBitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath()); 
         img.setImageBitmap(myBitmap); 
        } 

       }   
       break; 
      } 
     } 

     /** 
     * Returns path of the file specified by content Uri 
     */ 
     public String getRealPathFromURI(Uri contentUri) { 
      String[] proj = { MediaStore.Images.Media.DATA }; 
      Cursor cursor = managedQuery(contentUri, proj, null, null, null); 
      int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA); 
      cursor.moveToFirst(); 
      String path = cursor.getString(column_index); 
      cursor.close(); 
      return path; 
     }