【发布时间】：2022-01-01 11:46:51
【问题描述】：
我目前有一个对话框弹出，允许用户为配方添加标题和描述，单击“提交”按钮后，该配方将被添加到回收站视图中。我还想添加功能，以便用户可以在此对话框中拍照，一旦对话框关闭，它将显示在弹出窗口和回收站视图中。我现在的问题是我似乎无法在对话框中调用 onActivityResult，这意味着它无法引用 ImageView。当我将 ImageView 设为全局时，我的应用程序崩溃了。我认为这与打开相机后对话框中的 ImageView 被关闭，因此 ImageView 对象为 null 的事实有关？
任何指导将不胜感激。
import android.Manifest;
import android.app.Dialog;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.provider.MediaStore;
import androidx.annotation.Nullable;
import androidx.appcompat.widget.SearchView;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.RecyclerView;
import androidx.recyclerview.widget.SimpleItemAnimator;
import androidx.recyclerview.widget.DefaultItemAnimator;
import androidx.recyclerview.widget.LinearLayoutManager;
import android.view.Gravity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
ArrayList<NoteModel> arrayList;
RecyclerView recyclerView;
FloatingActionButton actionButton;
DatabaseHelper database_helper;
NotesAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
actionButton = (FloatingActionButton) findViewById(R.id.add);
database_helper = new DatabaseHelper(this);
displayNotes();
actionButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
showDialog();
}
});
}
//display notes list
public void displayNotes() {
arrayList = new ArrayList<>(database_helper.getNotes());
recyclerView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));
recyclerView.setItemAnimator(new DefaultItemAnimator());
adapter = new NotesAdapter(getApplicationContext(), this, arrayList);
recyclerView.setAdapter(adapter);
}
//display dialog
public void showDialog() {
final EditText title, des;
Button submit;
Button takepicture;
ImageView imageView;
final Dialog dialog = new Dialog(this);
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
WindowManager.LayoutParams params = new WindowManager.LayoutParams();
dialog.setContentView(R.layout.dialog);
View v = getWindow().getDecorView();
v.setBackgroundResource(android.R.color.transparent);
params.copyFrom(dialog.getWindow().getAttributes());
params.height = WindowManager.LayoutParams.MATCH_PARENT;
params.width = WindowManager.LayoutParams.MATCH_PARENT;
params.gravity = Gravity.CENTER;
dialog.getWindow().setAttributes(params);
dialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
dialog.show();
title = (EditText) dialog.findViewById(R.id.title);
des = (EditText) dialog.findViewById(R.id.description);
submit = (Button) dialog.findViewById(R.id.submit);
takepicture = (Button) dialog.findViewById(R.id.takepicture);
imageView = (ImageView) findViewById(R.id.image_view);
if (ContextCompat.checkSelfPermission(MainActivity.this,
Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{
Manifest.permission.CAMERA},
100);
}
submit.setOnClickListener(new View.OnClickListener() {
;
@Override
public void onClick(View v) {
if (title.getText().toString().isEmpty()) {
title.setError("Please Enter Title");
} else if (des.getText().toString().isEmpty()) {
des.setError("Please Enter Description");
} else {
database_helper.addNotes(title.getText().toString(), des.getText().toString());
dialog.cancel();
displayNotes();
}
}
});
takepicture.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(intent, 100);
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data)
{
if (requestCode == 100) {
Bitmap captureImage = (Bitmap) data.getExtras().get("data");
imageView.setImageBitmap(captureImage);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main_menu, menu);
MenuItem item = menu.findItem(R.id.action_search);
SearchView searchView = (SearchView) item.getActionView();
searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
@Override
public boolean onQueryTextSubmit(String s) {
return false;
}
@Override
public boolean onQueryTextChange(String newText) {
adapter.getFilter().filter(newText);
return false;
}
});
return super.onCreateOptionsMenu(menu);
}
}
【问题讨论】：
-
当相机应用程序到达顶部时，您的活动将被终止。如果相机应用程序关闭，您的活动将重新创建。不仅 imageView==null，而且你的对话框也消失了。
标签： java android android-activity android-recyclerview