Java Android Studio:将图像保存在SD卡中
我保存了一个学校项目,该项目处理的是一个包含托管在服务器上的图像的列表视图。Java Android Studio:将图像保存在SD卡中,java,android,Java,Android,我保存了一个学校项目,该项目处理的是一个包含托管在服务器上的图像的列表视图。 当有人从列表中选择一幅图像时,它会在另一个布局中以“原始”大小显示,即使在这里,一切都很顺利。 但也要询问图像显示器何时可以选择将其保存到SD卡,这是我不能做的部分 这是我做的代码: public class MainActivity extends AppCompatActivity { private ListView listView; private ProgressDialog progressDialog
当有人从列表中选择一幅图像时,它会在另一个布局中以“原始”大小显示,即使在这里,一切都很顺利。
但也要询问图像显示器何时可以选择将其保存到SD卡,这是我不能做的部分 这是我做的代码:
public class MainActivity extends AppCompatActivity {
private ListView listView;
private ProgressDialog progressDialog;
ArrayList asuntos=new ArrayList();
ArrayList imagen=new ArrayList();
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolBar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolBar);
listView=(ListView) findViewById(R.id.list);
progressDialog = new ProgressDialog(this);
progressDialog.setCancelable(false);
lista o=new lista();
o.obtenerAvisos();
}
public class lista {
public void obtenerAvisos() {
asuntos.clear();
imagen.clear();
String tag_string_req = "req_data";
progressDialog.setMessage("Conectando...");
showDialog();
StringRequest strReq = new StringRequest(Request.Method.POST, AppURLs.URL, new Response.Listener<String>() {
public void onResponse(String response) {
hideDialog();
try {
JSONArray jsonArray = new JSONArray(response);
for (int i = 0; i < jsonArray.length(); i++) {
asuntos.add(jsonArray.getJSONObject(i).getString("asunto"));
imagen.add(jsonArray.getJSONObject(i).getString("publicacion"));
}
listView.setAdapter(new ImagenAdaptador(getApplicationContext()));
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(), error.getMessage(), Toast.LENGTH_LONG).show();
hideDialog();
}
}) {
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("tag", "data");
return params;
}
};
AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
}
}
private void showDialog() {
if (!progressDialog.isShowing())
progressDialog.show();
}
private void hideDialog() {
if (progressDialog.isShowing())
progressDialog.dismiss();
}
public class ImagenAdaptador extends BaseAdapter {
Context ctx;
LayoutInflater layoutInflater;
SmartImageView smartImageView;
TextView tvasunto;
public ImagenAdaptador(Context applicationContext) {
this.ctx=applicationContext;
layoutInflater=(LayoutInflater)ctx.getSystemService(LAYOUT_INFLATER_SERVICE);
}
public int getCount() {
return imagen.size();
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewGroup viewGroup=(ViewGroup) layoutInflater.inflate(R.layout.activity_main_items,null);
smartImageView=(SmartImageView)viewGroup.findViewById(R.id.imagen1);
tvasunto=(TextView) viewGroup.findViewById(R.id.tvAsunto);
final String urlfinal="http://192.168.43.45/InfoTec/publicaciones/"+imagen.get(position).toString();
Rect rect=new Rect(smartImageView.getLeft(), smartImageView.getTop(), smartImageView.getRight(), smartImageView.getBottom());
smartImageView.setImageUrl(urlfinal, rect);
tvasunto.setText(asuntos.get(position).toString());
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Intent intent = new Intent(MainActivity.this, Visor.class);
intent.putExtra("arg", asuntos.get(position).toString());
intent.putExtra("arg2",imagen.get(position).toString());
startActivity(intent);
}
});
return viewGroup;
}
}
}
如果显示所选图像,但不是现在,则在事件中如何处理数据,请单击下载按钮。解决方案是什么?首先,您需要获取位图。您可以将其作为对象位图,也可以尝试从ImageView获取,例如:
BitmapDrawable drawable = (BitmapDrawable) mImageView1.getDrawable();
Bitmap bitmap = drawable.getBitmap();
然后,您必须从SD卡访问目录(文件对象),例如:
File sdCardDirectory = Environment.getExternalStorageDirectory();
接下来,创建用于图像存储的特定文件:
File image = new File(sdCardDirectory, "test.png");
之后,由于位图的压缩方法,您只需编写位图,例如:
boolean success = false;
// Encode the file as a PNG image.
FileOutputStream outStream;
try {
outStream = new FileOutputStream(image);
bitmap.compress(Bitmap.CompressFormat.PNG, 100, outStream);
/* 100 to keep full quality of the image */
outStream.flush();
outStream.close();
success = true;
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
最后,如果需要,只需处理布尔结果。例如:
if (success) {
Toast.makeText(getApplicationContext(), "Image saved with success",
Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getApplicationContext(),
"Error during image saving", Toast.LENGTH_LONG).show();
}
不要忘记在清单中添加以下权限:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
最好创建一个对话框,让用户选择照片的存储位置。请记住,安卓设备有很多种,它们可能会有所不同。非常好用,非常感谢。当然,我必须阅读更多关于Android中使用的资源的信息,我试图找到另一种与之无关的方式。
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>