将网格视图中的图像打开到新活动中

Question

我创建了一个显示来自 SD 卡中特定文件夹的图像的网格视图。我能够获得项目位置，但不幸的是，我面临在全屏图像活动中显示所选图像的问题。我认为使用其位置获取图像路径存在问题。非常感谢您的帮助。

这是 Gridview 活动

public class print extends AppCompatActivity {

public class ImageAdapter extends BaseAdapter {

    private Context mContext;
    ArrayList<String> itemList = new ArrayList<String>();

    public ImageAdapter(Context c) {
        mContext = c;
    }

    void add(String path){
        itemList.add(path);
    }

    @Override
    public int getCount() {
        return itemList.size();
    }

    @Override
    public Object getItem(int arg0) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ImageView imageView;
        if (convertView == null) {  // if it's not recycled, initialize some attributes
            imageView = new ImageView(mContext);
            imageView.setLayoutParams(new GridView.LayoutParams(700, 1150));
            imageView.setScaleType(ImageView.ScaleType.FIT_XY);
            imageView.setPadding(1, 1, 1, 1);
        } else {
            imageView = (ImageView) convertView;
        }

        Bitmap bm = decodeSampledBitmapFromUri(itemList.get(position), 220, 220);

        imageView.setImageBitmap(bm);
        return imageView;
    }



    public Bitmap decodeSampledBitmapFromUri(String path, int reqWidth, int reqHeight) {

        Bitmap bm = null;
        // First decode with inJustDecodeBounds=true to check dimensions
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(path, options);

        // Calculate inSampleSize
        options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);

        // Decode bitmap with inSampleSize set
        options.inJustDecodeBounds = false;
        bm = BitmapFactory.decodeFile(path, options);

        return bm;
    }

    public int calculateInSampleSize(

            BitmapFactory.Options options, int reqWidth, int reqHeight) {
        // Raw height and width of image
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;

        if (height > reqHeight || width > reqWidth) {
            if (width > height) {
                inSampleSize = Math.round((float)height / (float)reqHeight);
            } else {
                inSampleSize = Math.round((float)width / (float)reqWidth);
            }
        }

        return inSampleSize;
    }

}

ImageAdapter myImageAdapter;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    ActionBar actionBar = getSupportActionBar();
    actionBar.hide();
    setContentView(R.layout.activity_print);

    GridView gridView = (GridView) findViewById(R.id.gridView);
    myImageAdapter = new ImageAdapter(this);
    gridView.setAdapter(myImageAdapter);

    String ExternalStorageDirectoryPath = Environment
            .getExternalStorageDirectory()
            .getAbsolutePath();

    String targetPath = ExternalStorageDirectoryPath + "/sdfolder/";


    File targetDirector = new File(targetPath);

    File[] files = targetDirector.listFiles();
    for (File file : files){
        myImageAdapter.add(file.getAbsolutePath());
    }

    gridView.setOnItemClickListener(myOnItemClickListener);
}

AdapterView.OnItemClickListener myOnItemClickListener
        = new AdapterView.OnItemClickListener(){

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position,
                            long id) {
       // String prompt = (String)parent.getItemAtPosition(position).toString();


        Intent i = new Intent(print.this, DetailsActivity.class);
        Toast.makeText(print.this, "Position " + position,
                Toast.LENGTH_SHORT).show();
        i.putExtra("id", id);
         startActivity(i);
    }};

}

这是全屏活动

public class DetailsActivity extends AppCompatActivity {

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

    // Get position from intent passed from MainActivity.java
    Intent i = getIntent();

    int position = i.getExtras().getInt("id");

    // Open the Image adapter

    // Locate the ImageView in single_item_view.xml
    ImageView imageView = (ImageView) findViewById(R.id.image);

    // Get image and position from ImageAdapter.java and set into ImageView
    imageView.setImageResource(position);

}
}

Answer 1

您传递给 ImageView.setImageResource() 的整数必须是有效的可绘制资源 ID。根据您的代码，您实际传递给详细信息活动的是适配器特定的项目 ID，而且在您的情况下它始终为 0：

// ...
@Override
public long getItemId(int position) {
    // TODO Auto-generated method stub
    return 0;
}
// ...

解决方案：如果您只需要显示图片，您可以简单地将图片 URI 传递给 details 活动：

GridViewActivity.java

    Intent intent = new Intent(print.this, DetailsActivity.class);
    intent.putExtra("uri", myImageAdapter.itemList.get(position));
    startActivity(intent);

DetailsActivity.java

// ...
setContentView(R.layout.details_activity);

// Get position from intent passed from MainActivity.java
Intent intent = getIntent();
String imageUri = intent.getExtras().getString("uri");

Bitmap image = ...; // load the full size image using the imageUri

ImageView imageView.setImageBitmap(image);

您的活动之间无需共享列表。

Answer 2

您在第二个活动中需要您的ArrayList<String> itemList，然后执行以下操作：

public class DetailsActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.details_activity);
    Intent i = getIntent();
    int position = i.getExtras().getInt("id");
    ImageView imageView = (ImageView) findViewById(R.id.image);
          Bitmap bm = decodeSampledBitmapFromUri(itemList.get(position), 220, 220);
    ImageView imageView.setImageBitmap(bm);

}
}

或者您可以将图像 Uri 发送到下一个活动并像这样使用它：

public class DetailsActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.details_activity);
    Intent i = getIntent();
    String imageUri = i.getExtras().getString("uri");
    ImageView imageView = (ImageView) findViewById(R.id.image);
          Bitmap bm = decodeSampledBitmapFromUri(imageUri, 220, 220);
    ImageView imageView.setImageBitmap(bm);

}
}