我正在设计和 android 应用程序，我成功地从 firebase 获取数据(图像、标题和描述)，现在我试图通过使用 Intent 共享所有这些数据......但我每次都失败了......请帮助解决我的问题。这是我的 Activity 页面，我正在其中实现共享数据功能。
MainActivity.Java
package com.timts.swipenews;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.net.Uri;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Adapter;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import com.timts.swipenews.Adapter.MyAdapter;
import com.timts.swipenews.Listener.IFirebaseLoadDone;
import com.timts.swipenews.Model.Movie;
import com.timts.swipenews.Transformer.DeapthPageTransformer;
import java.io.File;
import java.io.FileOutputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class MainActivity extends AppCompatActivity implements IFirebaseLoadDone {
private static final String TAG = "MainActivity";
ViewPager viewPager;
MyAdapter adapter;
DatabaseReference movies;
IFirebaseLoadDone iFirebaseLoadDone;
TextView mTitleTv, mDetailTV;
ImageView mImageIv, mShareBtn;
Bitmap bitmap;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTitleTv = findViewById(R.id.movie_title);
mDetailTV = findViewById(R.id.movie_description);
mImageIv = findViewById(R.id.movie_image);
mShareBtn = findViewById(R.id.img_shr);
//ge dat from server
byte[] bytes = getIntent().getByteArrayExtra("image");
String title = getIntent().getStringExtra("title");
String desc = getIntent().getStringExtra("description");
Bitmap bmp = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
//set data to views
mTitleTv.setText(title);
mDetailTV.setText(desc);
mImageIv.setImageBitmap(bmp);
//get image from image view
bitmap = ((BitmapDrawable) mImageIv.getDrawable()).getBitmap();
movies = FirebaseDatabase.getInstance().getReference("Movies");
iFirebaseLoadDone = this;
loadMovie();
viewPager = (ViewPager) findViewById(R.id.view_pager);
viewPager.setPageTransformer(true, new DeapthPageTransformer());
//share btn click handle
mShareBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
shareImage();
}
});
}
private void shareImage() {
try {
//get title and description save in string s
String s = mTitleTv.getText().toString() + "\n" + mDetailTV.getText().toString();
File file = new File(getExternalCacheDir(), "sample.png");
FileOutputStream fOut = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.PNG, 100, fOut);
fOut.flush();
fOut.close();
file.setReadable(true, false);
//intent to share image and text
Intent intent = new Intent(Intent.ACTION_SEND);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.putExtra(Intent.EXTRA_TEXT, s);//put the text
intent.putExtra(Intent.EXTRA_STREAM, Uri.fromFile(file));
intent.setType("image/png");
startActivity(Intent.createChooser(intent, "Share Via"));
} catch (Exception e) {
Toast.makeText(this, e.getMessage(), Toast.LENGTH_SHORT).show();
}
}
private void loadMovie() {
movies.addListenerForSingleValueEvent(new ValueEventListener() {
List<Movie> movieList = new ArrayList<>();
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot movieSnapShot : dataSnapshot.getChildren()) {
movieList.add(movieSnapShot.getValue(Movie.class));
iFirebaseLoadDone.onFirebaseLoadSuccess(movieList);
}
Collections.reverse(movieList);
adapter.notifyDataSetChanged();
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
iFirebaseLoadDone.onFirebaseLoadFailed(databaseError.getMessage());
}
});
}
@Override
public void onFirebaseLoadSuccess(List<Movie> movieList) {
adapter = new MyAdapter(this, movieList);
viewPager.setAdapter(adapter);
}
@Override
public void onFirebaseLoadFailed(String message) {
Toast.makeText(this, "" + message, Toast.LENGTH_SHORT).show();
}
}
日志
2019-04-04 11:33:19.878 26508-26508/com.timts.swipenews E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.timts.swipenews, PID: 26508
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.timts.swipenews/com.timts.swipenews.MainActivity}: java.lang.NullPointerException: Attempt to get length of null array
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3121)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3260)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1976)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6912)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:860)
Caused by: java.lang.NullPointerException: Attempt to get length of null array
at com.timts.swipenews.MainActivity.onCreate(MainActivity.java:74)
at android.app.Activity.performCreate(Activity.java:7144)
at android.app.Activity.performCreate(Activity.java:7135)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1293)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3101)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3260)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1976)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6912)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:860)
最佳答案
您在第 74 行得到 NullPointerException。您的 Intent 值可以是 null，尤其是 getIntent().getByteArrayExtra("image")。 logcat 显示 Attempt to get the length of null array。您应该确保该数组不是 null。最好的方法是调试。
编辑:
byte[] bytes = getIntent().getByteArrayExtra("image");
String title = getIntent().getStringExtra("title");
String desc = getIntent().getStringExtra("description");
Bitmap bmp = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
Drawable drawable = new BitmapDrawable(getResources(), bitmap);
//set data to views
mTitleTv.setText(title);
mDetailTV.setText(desc);
mImageIv.setImageDrawable(drawable)
关于java - 如何使用 Intent 共享从 firebase 服务器获取的数据(图像、标题和描述)...？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/55509410/