如何压缩URI图像

Question

我对编程还很陌生，我想将图像导入我的应用程序并在那里显示。问题是，每当我在应用程序中添加照片时，由于Java中的outOfMemory错误，应用程序不久就会崩溃。在添加之前，我需要压缩图像，但我绝对不知道如何压缩，有人能帮我吗？

我的代码：

主要活动：

import android.content.ClipData;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.net.Uri;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private Button btn;
int PICK_IMAGE_MULTIPLE = 1;
String imageEncoded;
List<String> imagesEncodedList;
private GridView gvGallery;
private GalleryAdapter galleryAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = findViewById(R.id.btn);
gvGallery = (GridView)findViewById(R.id.gv);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent();
intent.setType("image/*");
intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent,"Bild(er) wählen"), PICK_IMAGE_MULTIPLE);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_camera) {
Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
}
return true;
}
return super.onOptionsItemSelected(item);
}
static final int REQUEST_IMAGE_CAPTURE = 1;
static final int PICK_IMAGE = 1;
//private void dispatchTakePictureIntent() {
//    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
//    if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
//        startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
//    }
//}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
try {
// When an Image is picked
if (requestCode == PICK_IMAGE_MULTIPLE && resultCode == RESULT_OK
&& null != data) {
// Get the Image from data
String[] filePathColumn = { MediaStore.Images.Media.DATA };
imagesEncodedList = new ArrayList<String>();
if(data.getData()!=null){
Uri mImageUri=data.getData();
// Get the cursor
Cursor cursor = getContentResolver().query(mImageUri,
filePathColumn, null, null, null);
// Move to first row
cursor.moveToFirst();
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
imageEncoded  = cursor.getString(columnIndex);
cursor.close();
ArrayList<Uri> mArrayUri = new ArrayList<Uri>();
mArrayUri.add(mImageUri);
galleryAdapter = new GalleryAdapter(getApplicationContext(),mArrayUri);
gvGallery.setAdapter(galleryAdapter);
gvGallery.setVerticalSpacing(gvGallery.getHorizontalSpacing());
ViewGroup.MarginLayoutParams mlp = (ViewGroup.MarginLayoutParams) gvGallery
.getLayoutParams();
mlp.setMargins(0, gvGallery.getHorizontalSpacing(), 0, 0);
} else {
if (data.getClipData() != null) {
ClipData mClipData = data.getClipData();
ArrayList<Uri> mArrayUri = new ArrayList<Uri>();
for (int i = 0; i < mClipData.getItemCount(); i++) {
ClipData.Item item = mClipData.getItemAt(i);
Uri uri = item.getUri();
mArrayUri.add(uri);
// Get the cursor
Cursor cursor = getContentResolver().query(uri, filePathColumn, null, null, null);
// Move to first row
cursor.moveToFirst();
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
imageEncoded  = cursor.getString(columnIndex);
imagesEncodedList.add(imageEncoded);
cursor.close();
galleryAdapter = new GalleryAdapter(getApplicationContext(),mArrayUri);
gvGallery.setAdapter(galleryAdapter);
gvGallery.setVerticalSpacing(gvGallery.getHorizontalSpacing());
ViewGroup.MarginLayoutParams mlp = (ViewGroup.MarginLayoutParams) gvGallery
.getLayoutParams();
mlp.setMargins(0, gvGallery.getHorizontalSpacing(), 0, 0);
}
Log.v("LOG_TAG", "Selected Images" + mArrayUri.size());
}
}
} else {
Toast.makeText(this, "Keine Bilder ausgewählt!",
Toast.LENGTH_LONG).show();
}
} catch (Exception e) {
Toast.makeText(this, "Fehler", Toast.LENGTH_LONG)
.show();
}
//if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
//    Bundle extras = data.getExtras();
//    Bitmap imageBitmap = (Bitmap) extras.get("data");
//    ImageView mImageView = new ImageView(this);
//    mImageView.setImageBitmap(imageBitmap);
//}
super.onActivityResult(requestCode, resultCode, data);
}
}

Gallery适配器：

import android.content.Context;
import android.net.Uri;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import java.util.ArrayList;
public class GalleryAdapter extends BaseAdapter {
private Context ctx;
private int pos;
private LayoutInflater inflater;
private ImageView ivGallery;
ArrayList<Uri> mArrayUri;
public GalleryAdapter(Context ctx, ArrayList<Uri> mArrayUri) {
this.ctx = ctx;
this.mArrayUri = mArrayUri;
}
@Override
public int getCount() {
return mArrayUri.size();
}
@Override
public Object getItem(int position) {
return mArrayUri.get(position);
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
pos = position;
inflater = (LayoutInflater) ctx
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View itemView = inflater.inflate(R.layout.gv_item, parent, false);
ivGallery = (ImageView) itemView.findViewById(R.id.ivGallery);
ivGallery.setImageURI(mArrayUri.get(position));
return itemView;
}

}

如果您需要更多信息，请随时询问！谢谢你帮我！

Answer 1

问题：应用程序的问题是android系统无法在屏幕上正确加载相对较大的位图，并且在尝试加载时超过了分配给此加载过程的内存限制。

解决方案：

快速解决方案：如何在Android中调整图像大小？

详细了解：

注意：有几个库遵循加载图像。您可以在应用程序中使用这些库来加载图像以最优化的方式。我们推荐Glide库尽可能快速、平滑地加载和显示图像。另外流行的图像加载库包括《广场上的毕加索》和《壁画》来自Facebook。这些库简化了大多数复杂的任务与Android上的位图和其他类型的图像关联。

点击此处链接：https://developer.android.com/topic/performance/graphics/load-bitmap

Answer 2

尝试直接获取位图，然后缩放它。

Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), mArrayUri.get(position));

这应该得到位图。

然后你可以把它缩小。我不会给出缩放的实现，但你会想要这种方法：

Bitmap.createScaledBitmap(Bitmap src, int dstWidth, int dstHeight, boolean filter)