如何读取手机中相册的图像文件

Question

对于以下的代码片段出现一个问题。实际上我是想读取手机中相册的图片。文件名为image2.jpg ，image3.jpg 的图片。但是报出了错误。
代码是：

public static Uri getRandomImage(ContentResolver resolver) {

    String secondo = "image2.jpg";
    String terzo = "image3.jpg";
    String quarto = "image4.jpg";
    String quinto = "image5.jpg";
    String sesto = "image6.jpg";
    String settimo = "image7.jpg";
    String ottavo = "image8.jpg";

    String[] projection = new String[] {
        BaseColumns._ID,
        MediaColumns.DATA,

    };



    Uri uri = Media.EXTERNAL_CONTENT_URI;

    Cursor cursor =  Media.query(resolver, uri, projection, null, MediaColumns._ID);
    if (cursor == null || cursor.getCount() <= 0) {
            return null;
    }

    cursor.moveToPosition(new Random().nextInt(cursor.getCount()));

    String completefilepath = cursor.getString(cursor.getColumnIndex(MediaColumns.DATA));
    if(completefilepath == secondo || completefilepath == terzo || completefilepath == quarto ||
            completefilepath == quinto || completefilepath == sesto || completefilepath == settimo ||
            completefilepath == ottavo){

        string = cursor.getString(1);

    }
    return Uri.withAppendedPath(uri, string);
}

LOGCAT：

E/AndroidRuntime(9147): FATAL EXCEPTION: main
E/AndroidRuntime(9147): java.lang.IllegalStateException: Unknown URL: content://media/external/images/media/null
E/AndroidRuntime(9147):     at android.os.Parcel.readException(Parcel.java:1268)
E/AndroidRuntime(9147):     at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:160)
E/AndroidRuntime(9147):     at android.database.DatabaseUtils.readExceptionWithFileNotFoundExceptionFromParcel(DatabaseUtils.java:125)
E/AndroidRuntime(9147):     at android.content.ContentProviderProxy.openAssetFile(ContentProviderNative.java:538)
E/AndroidRuntime(9147):     at android.content.ContentResolver.openAssetFileDescriptor(ContentResolver.java:467)
E/AndroidRuntime(9147):     at android.content.ContentResolver.openFileDescriptor(ContentResolver.java:380)
E/AndroidRuntime(9147):     at it.bisemanuDEV.slidepuzzle.TileView.getImageFromUri(TileView.java:559)
E/AndroidRuntime(9147):     at it.bisemanuDEV.slidepuzzle.TileView.newGame(TileView.java:156)
E/AndroidRuntime(9147):     at it.bisemanuDEV.slidepuzzle.SlidePuzzleActivity.onOptionsItemSelected(SlidePuzzleActivity.java:377)
E/AndroidRuntime(9147):     at android.app.Activity.onMenuItemSelected(Activity.java:2762)
E/AndroidRuntime(9147):     at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:730)
E/AndroidRuntime(9147):     at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:143)
E/AndroidRuntime(9147):     at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:855)
E/AndroidRuntime(9147):     at com.android.internal.view.menu.IconMenuView.invokeItem(IconMenuView.java:532)
E/AndroidRuntime(9147):     at com.android.internal.view.menu.IconMenuItemView.performClick(IconMenuItemView.java:122)
E/AndroidRuntime(9147):     at android.view.View$PerformClick.run(View.java:8819)
E/AndroidRuntime(9147):     at android.os.Handler.handleCallback(Handler.java:603)
E/AndroidRuntime(9147):     at android.os.Handler.dispatchMessage(Handler.java:92)
E/AndroidRuntime(9147):     at android.os.Looper.loop(Looper.java:123)
E/AndroidRuntime(9147):     at android.app.ActivityThread.main(ActivityThread.java:4627)
E/AndroidRuntime(9147):     at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime(9147):     at java.lang.reflect.Method.invoke(Method.java:521)
E/AndroidRuntime(9147):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
E/AndroidRuntime(9147):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
E/AndroidRuntime(9147):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

你可以参考这个方法，然后再自己变通一下
XML:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <ImageView
        android:id="@+id/imgView"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"></ImageView>
    <Button
        android:id="@+id/buttonLoadPicture"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="0"
        android:text="Load Picture"
        android:layout_gravity="center"></Button>
</LinearLayout>

class文件：

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class ImageGalleryDemoActivity extends Activity {


    private static int RESULT_LOAD_IMAGE = 1;


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

        Button buttonLoadImage = (Button) findViewById(R.id.buttonLoadPicture);
        buttonLoadImage.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View arg0) {

                Intent i = new Intent(
                        Intent.ACTION_PICK,
                        android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

                startActivityForResult(i, RESULT_LOAD_IMAGE);
            }
        });
    }


    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK && null != data) {
            Uri selectedImage = data.getData();
            String[] filePathColumn = { MediaStore.Images.Media.DATA };

            Cursor cursor = getContentResolver().query(selectedImage,
                    filePathColumn, null, null, null);
            cursor.moveToFirst();

            int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
            String picturePath = cursor.getString(columnIndex);
            cursor.close();

            ImageView imageView = (ImageView) findViewById(R.id.imgView);
            imageView.setImageBitmap(BitmapFactory.decodeFile(picturePath));

        }
    }
}