Android 单击浮动操作按钮时，应用程序正在崩溃
我使用浮动操作按钮从一个活动导航到另一个活动，但当我单击时，应用程序崩溃了，浮动操作按钮没有问题，问题是在另一个活动中导航了它。它被导航到uploadPost类Android 单击浮动操作按钮时，应用程序正在崩溃,android,fragment,Android,Fragment,我使用浮动操作按钮从一个活动导航到另一个活动，但当我单击时，应用程序崩溃了，浮动操作按钮没有问题，问题是在另一个活动中导航了它。它被导航到uploadPost类 public class uploadPost extends Fragment implements SelectPhotoDialog.OnPhotoSelectedListener { private static final String TAG = "uploadPost"; @Override
public class uploadPost extends Fragment implements SelectPhotoDialog.OnPhotoSelectedListener {
private static final String TAG = "uploadPost";
@Override
public void getImagePath(Uri imagePath) {
Log.d(TAG, "getImagePath: setting the image to imageview");
UniversalImageLoader.setImage(imagePath.toString(), mPostImage);
//assign to global variable
mSelectedBitmap = null;
mSelectedUri = imagePath;
}
@Override
public void getImageBitmap(Bitmap bitmap) {
Log.d(TAG, "getImageBitmap: setting the image to imageview");
mPostImage.setImageBitmap(bitmap);
//assign to a global variable
mSelectedUri = null;
mSelectedBitmap = bitmap;
}
//widgets
private ImageView mPostImage;
private EditText mTitle, mDescription, mPrice, mCountry, mStateProvince, mCity, mContactEmail,mCollege;
private Button mPost;
private ProgressBar mProgressBar;
//vars
private Bitmap mSelectedBitmap;
private Uri mSelectedUri;
private byte[] mUploadBytes;
private double mProgress = 0;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.activity_upload_post, container, false);
mPostImage = view.findViewById(R.id.post_image);
mTitle = view.findViewById(R.id.input_title);
mDescription = view.findViewById(R.id.input_description);
mPrice = view.findViewById(R.id.input_price);
mCountry = view.findViewById(R.id.input_country);
mStateProvince = view.findViewById(R.id.input_state_province);
mCity = view.findViewById(R.id.input_city);
mContactEmail = view.findViewById(R.id.input_email);
mCollege = view.findViewById(R.id.input_clg);
mPost = view.findViewById(R.id.btn_post);
mProgressBar = (ProgressBar) view.findViewById(R.id.progressBar);
mCountry.setText("India");
mStateProvince.setText("Maharashtra");
mCity.setText("Pune");
getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);
init();
return view;
}
private void init(){
mPostImage.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.d(TAG, "onClick: opening dialog to choose new photo");
SelectPhotoDialog dialog = new SelectPhotoDialog();
dialog.show(getFragmentManager(), getString(R.string.dialog_select_photo));
dialog.setTargetFragment(uploadPost.this, 1);
}
});
mPost.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.d(TAG, "onClick: attempting to post...");
if(!isEmpty(mTitle.getText().toString())
&& !isEmpty(mDescription.getText().toString())
&& !isEmpty(mPrice.getText().toString())
&& !isEmpty(mCountry.getText().toString())
&& !isEmpty(mStateProvince.getText().toString())
&& !isEmpty(mCity.getText().toString())
&& !isEmpty(mContactEmail.getText().toString())){
//we have a bitmap and no Uri
if(mSelectedBitmap != null && mSelectedUri == null){
uploadNewPhoto(mSelectedBitmap);
}
//we have no bitmap and a uri
else if(mSelectedBitmap == null && mSelectedUri != null){
uploadNewPhoto(mSelectedUri);
}
}else{
Toast.makeText(getActivity(), "You must fill out all the fields", Toast.LENGTH_SHORT).show();
}
}
});
}
private void uploadNewPhoto(Bitmap bitmap){
Log.d(TAG, "uploadNewPhoto: uploading a new image bitmap to storage");
BackgroundImageResize resize = new BackgroundImageResize(bitmap);
Uri uri = null;
resize.execute(uri);
}
private void uploadNewPhoto(Uri imagePath){
Log.d(TAG, "uploadNewPhoto: uploading a new image uri to storage.");
BackgroundImageResize resize = new BackgroundImageResize(null);
resize.execute(imagePath);
}
public class BackgroundImageResize extends AsyncTask<Uri, Integer, byte[]>{
Bitmap mBitmap;
public BackgroundImageResize(Bitmap bitmap) {
if(bitmap != null){
this.mBitmap = bitmap;
}
}
@Override
protected void onPreExecute() {
super.onPreExecute();
Toast.makeText(getActivity(), "compressing image", Toast.LENGTH_SHORT).show();
showProgressBar();
}
@Override
protected byte[] doInBackground(Uri... params) {
Log.d(TAG, "doInBackground: started.");
if(mBitmap == null){
try{
RotateBitmap rotateBitmap = new RotateBitmap();
mBitmap = rotateBitmap.HandleSamplingAndRotationBitmap(getActivity(), params[0]);
}catch (IOException e){
Log.e(TAG, "doInBackground: IOException: " + e.getMessage());
}
}
byte[] bytes = null;
Log.d(TAG, "doInBackground: megabytes before compression: " + mBitmap.getByteCount() / 1000000 );
bytes = getBytesFromBitmap(mBitmap, 100);
Log.d(TAG, "doInBackground: megabytes before compression: " + bytes.length / 1000000 );
return bytes;
}
@Override
protected void onPostExecute(byte[] bytes) {
super.onPostExecute(bytes);
mUploadBytes = bytes;
hideProgressBar();
//execute the upload task
executeUploadTask();
}
}
private void executeUploadTask(){
Toast.makeText(getActivity(), "uploading image", Toast.LENGTH_SHORT).show();
final String postId = FirebaseDatabase.getInstance().getReference().push().getKey();
final StorageReference storageReference = FirebaseStorage.getInstance().getReference()
.child("posts/users/" + FirebaseAuth.getInstance().getCurrentUser().getUid() +
"/" + postId + "/post_image");
UploadTask uploadTask = storageReference.putBytes(mUploadBytes);
uploadTask.addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
@Override
public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
Toast.makeText(getActivity(), "Post Success", Toast.LENGTH_SHORT).show();
//insert the download url into the firebase database
Uri firebaseUri = taskSnapshot.getDownloadUrl();
Log.d(TAG, "onSuccess: firebase download url: " + firebaseUri.toString());
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Post post = new Post();
post.setImage(firebaseUri.toString());
post.setCity(mCity.getText().toString());
post.setContact_email(mContactEmail.getText().toString());
post.setCountry(mCountry.getText().toString());
post.setDescription(mDescription.getText().toString());
post.setPost_id(postId);
post.setPrice(mPrice.getText().toString());
post.setState_province(mStateProvince.getText().toString());
post.setTitle(mTitle.getText().toString());
post.setUser_id(FirebaseAuth.getInstance().getCurrentUser().getUid());
post.setCollege(mCollege.getText().toString());
reference.child(getString(R.string.node_posts))
.child(postId)
.setValue(post);
resetFields();
}
}).addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
Toast.makeText(getActivity(), "could not upload photo", Toast.LENGTH_SHORT).show();
}
}).addOnProgressListener(new OnProgressListener<UploadTask.TaskSnapshot>() {
@Override
public void onProgress(UploadTask.TaskSnapshot taskSnapshot) {
double currentProgress = (100 * taskSnapshot.getBytesTransferred()) / taskSnapshot.getTotalByteCount();
if( currentProgress > (mProgress + 15)){
mProgress = (100 * taskSnapshot.getBytesTransferred()) / taskSnapshot.getTotalByteCount();
Log.d(TAG, "onProgress: upload is " + mProgress + "& done");
Toast.makeText(getActivity(), mProgress + "%", Toast.LENGTH_SHORT).show();
}
}
});
}
public static byte[] getBytesFromBitmap(Bitmap bitmap, int quality){
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, quality,stream);
return stream.toByteArray();
}
private void resetFields(){
UniversalImageLoader.setImage("", mPostImage);
mTitle.setText("");
mDescription.setText("");
mPrice.setText("");
mCountry.setText("India");
mStateProvince.setText("Maharashtra");
mCity.setText("Pune");
mContactEmail.setText("");
mCollege.setText("");
}
private void showProgressBar(){
mProgressBar.setVisibility(View.VISIBLE);
}
private void hideProgressBar(){
if(mProgressBar.getVisibility() == View.VISIBLE){
mProgressBar.setVisibility(View.INVISIBLE);
}
}
/**
* Return true if the @param is null
* @param string
* @return
*/
private boolean isEmpty(String string){
return string.equals("");
}
}
FATAL EXCEPTION: main
Process: codingwithmitch.com.forsale, PID: 13518
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{codingwithmitch.com.forsale/codingwithmitch.com.forsale.uploadPost}: java.lang.ClassCastException: codingwithmitch.com.forsale.uploadPost cannot be cast to android.app.Activity
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2561)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2724)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1473)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6123)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:757)
Caused by: java.lang.ClassCastException: codingwithmitch.com.forsale.uploadPost cannot be cast to android.app.Activity
at android.app.Instrumentation.newActivity(Instrumentation.java:1100)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2551)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2724)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1473)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6123)
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:fab="http://schemas.android.com/tools"
android:id="@+id/drawer"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/White"
android:fitsSystemWindows="true">
<android.support.design.widget.CoordinatorLayout
android:id="@+id/error"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="@+id/app_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/white"
android:elevation="10dp"
android:fitsSystemWindows="true">
<android.support.design.widget.CollapsingToolbarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<android.support.design.widget.TabLayout
android:id="@+id/tabs"
android:layout_width="match_parent"
android:layout_height="50dp"
app:layout_collapseMode="parallax">
</android.support.design.widget.TabLayout>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="@+id/viewpager_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior">
</android.support.v4.view.ViewPager>
<com.getbase.floatingactionbutton.FloatingActionButton
android:id="@+id/fab"
android:layout_width="42dp"
android:layout_height="53dp"
android:layout_gravity="bottom|end"
android:layout_margin="@dimen/fab_margin"
android:scaleType="center"
android:src="@drawable/ic_camera_alt_black_24dp"
app:fabSize="normal"
fab:layout_editor_absoluteX="342dp"
fab:layout_editor_absoluteY="458dp">
</com.getbase.floatingactionbutton.FloatingActionButton>
</android.support.design.widget.CoordinatorLayout>
<android.support.design.widget.NavigationView
android:id="@+id/navigation_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="start"
app:headerLayout="@layout/header"
app:menu="@menu/nav_menu"></android.support.design.widget.NavigationView>
</android.support.v4.widget.DrawerLayout>
您将收到以下错误： 无法强制转换为android.app.Activity 因为您试图将
uploadPost活动加载，但它扩展了片段
，因此您会出现“无法转换到android.app.Activity”错误
您必须决定是将其作为片段
还是作为活动
加载。如果要将uploadPost
作为活动加载
，则需要扩展到活动
而不是片段
编辑
如果希望继续将其用作片段
，则必须使用片段事务
在活动布局中添加片段
或替换片段
您可以替换片段
，如下示例所示：
Fragment fragment = new UploadPost();
if(fragment != null) {
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
//If you want to play around with different transaction animations
//fragmentTransaction.setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out);
fragmentTransaction.replace(R.id.content_main, fragment, "0");
fragmentTransaction.commit();
}
其中，R.id.content\u main
只是my main活动中的一个RelativeLayout
，由uploadPost
片段替换
正如0X0nosugar所指出的：将类名大写是java命名约定。请采用这种约定——否则您将使代码更难理解
编辑2
通常使用片段
交换容器活动
中的视图。例如，我使用它们与抽屉布局组合交换视图。在本例中，我将继续替换片段，但永远不会显式删除片段
例如，我将有一个与您的“SearchActivity”文件非常相似的xml布局文件。在
标记的正下方，我将引入一个id为android:id=“@+id/content\u main”
的RelativeLayout
。此RelativeLayout
只是一个虚拟容器视图，正在替换为我选择的片段中的任何内容。因此，您需要更改onClick
code来替换上面显示的片段
通过另一个操作，您可能希望删除该片段或用另一个片段替换它。。。这一切都取决于你的应用程序设计——我不知道。请显示当点击按钮时你是如何启动其他活动的。你想查看代码吗？是的，没错。logcat显示你有一个ClassCastException，你正在尝试操作uploadPost
，就好像它是一个活动一样。这不是一个活动
，因此在对其执行操作时会崩溃。我已更新了我的问题，请看一看，我必须将其作为一个片段加载，为此我必须这样做do@VishalSharma当前位置我已经编辑了答案。如果您需要更多信息来实现此功能，请编辑您的问题并提供SearchActivity
的xml布局——如果您希望在此处显示片段
我已附上我的SearchActivity的xml布局，请look@VishalSharma：：我希望我在“编辑2”中提供的信息对您有所帮助。如果没有关于应用程序的深入信息，就很难获得更多指导
Fragment fragment = new UploadPost();
if(fragment != null) {
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
//If you want to play around with different transaction animations
//fragmentTransaction.setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out);
fragmentTransaction.replace(R.id.content_main, fragment, "0");
fragmentTransaction.commit();
}