Question

我是第一次使用Firebase，我想用手机图库中的任何图片填充ImageView，但是每次运行该程序时，它都会崩溃。单击Floating Action Button会弹出一个弹出窗口，其中包含两个编辑文本和一个大图像视图，需要在Firebase上上传图像。该想法是，单击ImageView可以直接将您带到Gallery中进行选择。代码工作正常，直到我尝试从图库中插入图片为止。 imageUserDesc是问题所在，我无法弄清楚自己做错了什么。

MainActivity.java
public class Home extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

FirebaseAuth firebaseAuth;
FirebaseUser currentUser;
Dialog addPost;
ProgressBar progressBar;
ImageView imageUserDP, imageUserDesc, imageUserBtn;
EditText userTitle, userDesc;
Uri descriptionImageURI = null;
//Button addImage;
private static final int requestCode = 2;
private static  final int openGallery = 2;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_home2);
    progressBar = findViewById(R.id.pop_up_progress);
    Toolbar toolbar = findViewById(R.id.toolbar);
    imageUserDesc = findViewById(R.id.pop_up_description_image);
    //addImage = findViewById(R.id.pop_up_add_image);
    setSupportActionBar(toolbar);

    FloatingActionButton fab = findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            popUp();
        }
    });

    firebaseAuth = FirebaseAuth.getInstance();
    currentUser = firebaseAuth.getCurrentUser();
    DrawerLayout drawer = findViewById(R.id.drawer_layout);
    NavigationView navigationView = findViewById(R.id.nav_view);

    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.addDrawerListener(toggle);
    toggle.syncState();
    navigationView.setNavigationItemSelectedListener(this);

    UpdateHeader();

    imageUserDesc.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            checkselfPermission();
        }
    });

}



    //imageUserDesc = (ImageView)findViewById(R.id.pop_up_description_image);





private void openGallery() {
    Intent galleryIntent = new Intent(Intent.ACTION_GET_CONTENT);
    galleryIntent.setType("image/*");
    startActivityForResult(galleryIntent, openGallery);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == RESULT_OK && resultCode == openGallery && data != null) {
        descriptionImageURI = data.getData();
    }
}

private void checkselfPermission() {
    if(ContextCompat.checkSelfPermission(Home.this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {

        if (ActivityCompat.shouldShowRequestPermissionRationale(Home.this, Manifest.permission.READ_EXTERNAL_STORAGE)) {
            Toast.makeText(Home.this, "Grant Access Please", Toast.LENGTH_SHORT).show();
        }
        else {
            ActivityCompat.requestPermissions(Home.this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, requestCode);
        }
    }
    else {
        openGallery();
    }
}

private void popUp() {

    addPost = new Dialog(this);
    addPost.setContentView(R.layout.pop_up_post);
    addPost.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
    addPost.getWindow().setLayout(Toolbar.LayoutParams.MATCH_PARENT, Toolbar.LayoutParams.WRAP_CONTENT);
    addPost.getWindow().getAttributes().gravity = Gravity.TOP;
    addPost.show();

    imageUserDP = addPost.findViewById(R.id.pop_up_image);
    imageUserDesc = addPost.findViewById(R.id.pop_up_description_image);
    imageUserBtn = addPost.findViewById(R.id.pop_up_button);
    userTitle = addPost.findViewById(R.id.pop_up_title);
    userDesc = addPost.findViewById(R.id.pop_up_description);
    progressBar = addPost.findViewById(R.id.pop_up_progress);

    imageUserBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            progressBar.setVisibility(View.VISIBLE);
            imageUserBtn.setVisibility(View.INVISIBLE);
        }
    });

    Glide.with(this).load(currentUser.getPhotoUrl()).into(imageUserDP);
}

XML 

<ImageView
        android:background="#2d2d2d"
        android:id="@+id/pop_up_description_image"
        android:layout_width="0dp"
        android:layout_height="225dp"
        android:layout_marginTop="107dp"
        android:scaleType="centerCrop"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:srcCompat="@tools:sample/backgrounds/scenic" />

Answer 1

我一直想出这一次哪里出错了。应该从popUp（）方法内部单击imageUserDesc，因为根据我的理解，所有Dialog小部件都在其中声明了。我们需要做的就是将以下内容添加到方法中：

private void popUp（）{

    addPost = new Dialog(this);
    addPost.setContentView(R.layout.pop_up_post);
    addPost.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
    addPost.getWindow().setLayout(Toolbar.LayoutParams.MATCH_PARENT, Toolbar.LayoutParams.WRAP_CONTENT);
    addPost.getWindow().getAttributes().gravity = Gravity.TOP;
    addPost.show();

    imageUserDP = addPost.findViewById(R.id.pop_up_image);
    imageUserDesc = addPost.findViewById(R.id.pop_up_description_image);
    imageUserBtn = addPost.findViewById(R.id.pop_up_button);
    userTitle = addPost.findViewById(R.id.pop_up_title);
    userDesc = addPost.findViewById(R.id.pop_up_description);
    progressBar = addPost.findViewById(R.id.pop_up_progress);

    imageUserBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            progressBar.setVisibility(View.VISIBLE);
            imageUserBtn.setVisibility(View.INVISIBLE);
        }
    });

    Glide.with(this).load(currentUser.getPhotoUrl()).into(imageUserDP);

    setDescImage();
}

private void setDescImage() {
    imageUserDesc.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            checkselfPermission();
        }
    });
}

图像视图的java.lang.NullPointerException

1 个答案: