Android 添加第一个项目时回收视图项目动画崩溃
我正在开发一个小应用程序,用户可以在其中发布内容和评论文章。我正在使用github上的Instamaterial项目作为参考 当用户发布新评论时,有一个带有动画的评论活动。一切都很好。。。但是当我发布第一条评论时。。。应用程序正在崩溃,没有显示我花了一整天的时间尝试的评论动画(滚动到顶部)。。。但没有找到解决办法Android 添加第一个项目时回收视图项目动画崩溃,android,android-recyclerview,Android,Android Recyclerview,我正在开发一个小应用程序,用户可以在其中发布内容和评论文章。我正在使用github上的Instamaterial项目作为参考 当用户发布新评论时,有一个带有动画的评论活动。一切都很好。。。但是当我发布第一条评论时。。。应用程序正在崩溃,没有显示我花了一整天的时间尝试的评论动画(滚动到顶部)。。。但没有找到解决办法 public class CommentsActivity extends AppCompatActivity implements SendCommentButton.OnSend
public class CommentsActivity extends AppCompatActivity implements SendCommentButton.OnSendClickListener {
public static final String ARG_DRAWING_START_LOCATION = "arg_drawing_start_location";
LinearLayout contentRoot;
RecyclerView rvComments;
LinearLayout llAddComment;
EditText etComment;
SendCommentButton btnSendComment;
private CommentsAdapter commentsAdapter;
private int drawingStartLocation;
Toolbar toolbar;
private int currentPostID;
DatabaseHelper db;
private PreferencesManager preferencesManager;
ArrayList<PostResponse.PostComments> comments;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_comments);
toolbar = (Toolbar) findViewById(R.id.toolbar);
contentRoot = (LinearLayout) findViewById(R.id.contentRoot);
rvComments = (RecyclerView) findViewById(R.id.rvComments);
llAddComment = (LinearLayout) findViewById(R.id.llAddComment);
etComment = (EditText) findViewById(R.id.etComment);
btnSendComment = (SendCommentButton) findViewById(R.id.btnSendComment);
preferencesManager = new PreferencesManager(CommentsActivity.this);
db = new DatabaseHelper(CommentsActivity.this);
setupToolbar();
setupComments();
setupSendCommentButton();
drawingStartLocation = getIntent().getIntExtra(ARG_DRAWING_START_LOCATION, 0);
if (savedInstanceState == null) {
contentRoot.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
@Override
public boolean onPreDraw() {
contentRoot.getViewTreeObserver().removeOnPreDrawListener(this);
startIntroAnimation();
return true;
}
});
}
}
protected void setupToolbar() {
if (toolbar != null) {
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayShow
HomeEnabled(true);
toolbar.setNavigationIcon(R.mipmap.ic_menu_cancel);
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
onBackPressed();
}
});
}
}
private void setupComments() {
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
rvComments.setLayoutManager(linearLayoutManager);
rvComments.setHasFixedSize(true);
currentPostID = getIntent().getIntExtra(PostResponse.KEY_ID, -1);
comments = db.getCommentsByPostID(currentPostID);
commentsAdapter = new CommentsAdapter(this, comments);
rvComments.setAdapter(commentsAdapter);
rvComments.setOverScrollMode(View.OVER_SCROLL_NEVER);
rvComments.setOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
if (newState == RecyclerView.SCROLL_STATE_DRAGGING) {
commentsAdapter.setAnimationsLocked(true);
}
}
});
}
private void setupSendCommentButton() {
btnSendComment.setOnSendClickListener(this);
}
private void startIntroAnimation() {
ViewCompat.setElevation(getToolbar(), 0);
contentRoot.setScaleY(0.1f);
contentRoot.setPivotY(drawingStartLocation);
llAddComment.setTranslationY(200);
contentRoot.animate()
.scaleY(1)
.setDuration(200)
.setInterpolator(new AccelerateInterpolator())
.setListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
ViewCompat.setElevation(getToolbar(), Utils.dpToPx(8));
animateContent();
}
})
.start();
}
private void animateContent() {
commentsAdapter.updateItems();
llAddComment.animate().translationY(0)
.setInterpolator(new DecelerateInterpolator())
.setDuration(200)
.start();
}
@Override
public void onBackPressed() {
ViewCompat.setElevation(getToolbar(), 0);
contentRoot.postDelayed(new Runnable() {
@Override
public void run() {
contentRoot.animate()
.translationY(Utils.getScreenHeight(CommentsActivity.this))
.setDuration(200)
.setListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
CommentsActivity.super.onBackPressed();
overridePendingTransition(0, 0);
}
})
.start();
}
}, 100);
}
@Override
public void onSendClickListener(View v) {
if (validateComment()) {
publishComment(etComment.getText().toString());
PostResponse.PostComments newComment = new PostResponse().new PostComments();
newComment.user_id = Integer.parseInt(preferencesManager.getUserID());
newComment.comment = etComment.getText().toString();
newComment.post_id = currentPostID;
commentsAdapter.addItem(newComment);
commentsAdapter.setAnimationsLocked(false);
commentsAdapter.setDelayEnterAnimation(true);
rvComments.smoothScrollBy(0, rvComments.getChildAt(0).getHeight() * commentsAdapter.getItemCount());
etComment.setText(null);
btnSendComment.setCurrentState(SendCommentButton.STATE_DONE);
}
}
private boolean validateComment() {
if (TextUtils.isEmpty(etComment.getText())) {
btnSendComment.startAnimation(AnimationUtils.loadAnimation(this, R.anim.shake_error));
return false;
}
return true;
}
private Toolbar getToolbar(){
return toolbar;
}
/************************************************
* VOLLEY CALLS TO PUBLISH A COMMENT
* *****************************************************/
private void publishComment(final String comment) {
//Code here
}
}
我知道你知道这是因为这句话-(你在评论中告诉我) 但是你知道这是方法调用吗<代码>rvComments.getChildAt(0.getHeight() 我的想法是,如果recyleView是空的,那么调用
rvComments.getChildAt(0)
是对Null引用的引用,它是空的
因此,您可以NPE
,但如果已经添加了第一条注释,则列表大小为1,因此此行rvComments.getChildAt(0).getHeight()
实际上引用了一个视图对象地址
因此,我想你的解决方案是_,因为你知道它的首选高度查看或选择一个首选高度,然后硬编码并使用它。或者,如果您确实坚持使用视图高度,请在前进之前检查列表大小
...
commentsAdapter.setAnimationsLocked(false);
commentsAdapter.setDelayEnterAnimation(true);
if(rvComments.getChildCount() > 0){
//i guess you will have do rvComments.getChildAt(
//rvComments.getChildCount()-1) rather than below
rvComments.smoothScrollBy(0, rvComments.getChildAt(0).getHeight()
* commentsAdapter.getItemCount());
}else{
//do something else or find something to do to get the height you want
//and multiply. In short it means the first item.
...
显示代码,而且您的问题是,在您的onlick侦听器中,某些内容具有空引用。已更新问题以包含代码。为方便起见,先生,请将我指向第214行。您可以看到rvComments.smoothScrollBy(0,rvComments.getChildAt(0.getHeight()*commentsAdapter.getItemCount());这是添加第一条注释时创建空指针的行。我通常会检查……添加第一条注释后,rvComments.getChildAt(0)的值为144。我试着硬编码来查看。应用程序没有崩溃,但我看不到立即添加到回收视图的第一条评论。@VishalKumar,您是否能够避免@Elltz提到的崩溃?您现在的问题是它没有显示在recyclerview中,对吗?正是。。。但是在这通电话之前。。。我称之为->PostResponse.PostComments newComment=new PostResponse().new PostComments();newComment.user_id=Integer.parseInt(preferencesManager.getUserID());newComment.comment=etComment.getText().toString();newComment.post_id=currentposted;评论附加条款(新成员);它应该向recycleview添加一个项目(即第一条注释),我正在通知适配器中的更改。还是!!!您是否调用了
notifyDataSetChanged
或刷新列表的内容@VishalKumarYes!!!adapter的addItem()在行前执行此操作…这是导致问题的原因。目前正在处理其他社交功能,如/不喜欢、报告垃圾邮件…全部完成。。。仍然没有找到任何解决方案…尝试@VishalKumar是这一行notifyItemInserted(mItems.size()-1)代码>另外,当我发布我的答案时,它已经在那里了吗?还是你编辑的?
java.lang.NullPointerException
at com.test.abc.CommentsActivity.onSendClickListener(CommentsActivity.java:214)
at com.test.abc.views.SendCommentButton.onClick(SendCommentButton.java:80)
at android.view.View.performClick(View.java:4463)
at android.view.View$PerformClick.run(View.java:18770)
at android.os.Handler.handleCallback(Handler.java:808)
at android.os.Handler.dispatchMessage(Handler.java:103)
at android.os.Looper.loop(Looper.java:193)
rvComments.smoothScrollBy(0, rvComments.getChildAt(0).getHeight() *
commentsAdapter.getItemCount());
...
commentsAdapter.setAnimationsLocked(false);
commentsAdapter.setDelayEnterAnimation(true);
if(rvComments.getChildCount() > 0){
//i guess you will have do rvComments.getChildAt(
//rvComments.getChildCount()-1) rather than below
rvComments.smoothScrollBy(0, rvComments.getChildAt(0).getHeight()
* commentsAdapter.getItemCount());
}else{
//do something else or find something to do to get the height you want
//and multiply. In short it means the first item.
...