【发布时间】：2019-05-24 09:30:27
【问题描述】：
我正在构建一个应用程序，该应用程序的布局应该与 WhatsApp 在聊天活动中使用的布局几乎相同。它应该有一个文本输入、相机和视频录制选项。项目应在回收器内居中，当数据集更改时，回收器应滚动到最后添加的项目。当用户点击 Editext 键盘时，应该调整视图的大小，将回收器向上移动并关注 Dataset 中的最后一项。
对于滚动部分，我使用了 SmoothScrollToPosiotion，但是当包含图像或视频的项目被截断时，自动滚动也会停止工作。一个奇怪的错误是，当我通过单击 editText 打开键盘时，回收器几乎滚动到最后一项但不完全滚动，只有在多次重新打开键盘时才会完全显示该项目。
已经尝试过在谷歌上找到的解决方案，但这里没有预期的结果:(
编辑：几乎解决了，我刚刚在每个按钮的 onClickListener 内移动了 SmoothScrollToposition。现在它不会滚动到最后一个项目它只是滚动到最后一个项目之前但完全：D
这里有一些代码： （如果需要完整代码https://github.com/MikeSys/ChatApp）
MainActivity 布局
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<android.support.v7.widget.RecyclerView
android:background="@drawable/sfondo"
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="@+id/linearLayout"
app:layout_constraintTop_toTopOf="parent"
/>
<LinearLayout
android:id="@+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="55dp"
app:layout_constraintBottom_toBottomOf="parent"
android:orientation="horizontal">
<EditText
android:layout_gravity="center_vertical"
android:id="@+id/editText"
android:layout_width="255dp"
android:layout_height="55dp"
android:background="#0003A9F4"
android:hint="Scrivi"
android:padding="10dp" />
<Button
android:layout_gravity="center_vertical"
android:id="@+id/camera"
android:layout_width="50dp"
android:layout_height="50dp"
android:background="@drawable/camera"
/>
<Button
android:layout_gravity="center_vertical"
android:id="@+id/video"
android:layout_width="50dp"
android:layout_height="50dp"
android:background="@drawable/video"
/>
<Button
android:id="@+id/send"
android:layout_width="55dp"
android:layout_height="55dp"
android:background="@drawable/send" />
</LinearLayout>
</android.support.constraint.ConstraintLayout>
MainActivity 代码
public class MainActivity extends AppCompatActivity {
private ArrayList<ModelloDati> dati = new ArrayList<>();
private LinearLayoutManager linearLayoutManager;
private static final String VIDEO_DIRECTORY = "/Chat";
private myAdapter adapter;
public Uri passUri;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Variables-----------------------------------------
final RecyclerView recyclerView = findViewById(R.id.recyclerView);
Button video = findViewById(R.id.video);
Button camera = findViewById(R.id.camera);
Button send = findViewById(R.id.send);
final EditText editText = findViewById(R.id.editText);
// Layout Manager------------------------------------------------
linearLayoutManager = new LinearLayoutManager(MainActivity.this);
linearLayoutManager.setReverseLayout(true);
recyclerView.setLayoutManager(linearLayoutManager);
// Adapter-----------------------------------------
if(dati.size()> 1){
adapter = new myAdapter(dati, this);
//Removed SmoothScroll form here
adapter.notifyDataSetChanged();
recyclerView.setAdapter(adapter);
}
else{
Collections.reverse(dati);
adapter = new myAdapter(dati,this);
recyclerView.setAdapter(adapter);
}
// Click Listener Video button---------------------------------------------
video.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
startActivityForResult(intent,0);
//Added here SmotthScroll
recyclerView.smoothScrollToPosition(dati.size());
}
});
// Click Listener Camera button--------------------------------------------
camera.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(intent,1);
//Added here SmotthScroll
recyclerView.smoothScrollToPosition(dati.size());
}
});
// Click Listener Send button----------------------------------------------
send.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String string = editText.getText().toString();
dati.add(new ModelloDati(0,string));
editText.getText().clear();
//Added here SmotthScroll
recyclerView.smoothScrollToPosition(dati.size());
closeKeyboard();
}
});
}
private void closeKeyboard() {
View view = getCurrentFocus();
if(view != null){
InputMethodManager imm =
(InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(view.getWindowToken(),0);
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable
Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch (requestCode){
case 0:
try {
Uri contentURI = data.getData();
passUri = contentURI;
String recordedVideoPath = getPath(contentURI);
Log.d("frrr", recordedVideoPath);
saveVideoToInternalStorage(recordedVideoPath);
dati.add(new ModelloDati(2, contentURI));
}catch (Throwable o){Log.i("CAM","User aborted action");}
case 1:
try {
Bitmap bitmap = (Bitmap)data.getExtras().get("data");
dati.add(new ModelloDati(1,bitmap));
}catch(Throwable o){
Log.i("CAM","User aborted action");
}
}
}
private void saveVideoToInternalStorage (String filePath) {
File new file;
try {
File currentFile = new File(filePath);
File wallpaperDirectory = new
File(Environment.getExternalStorageDirectory() + VIDEO_DIRECTORY);
newfile = new File(wallpaperDirectory,
Calendar.getInstance().getTimeInMillis() + ".mp4");
if (!wallpaperDirectory.exists()) {
wallpaperDirectory.mkdirs();
}
if(currentFile.exists()){
InputStream in = new FileInputStream(currentFile);
OutputStream out = new FileOutputStream(newfile);
// Copy the bits from instream to outstream
byte[] buf = new byte[1024];
int len;
while ((len = in.read(buf)) > 0) {
out.write(buf, 0, len);
}
in.close();
out.close();
Log.v("vii", "Video file saved successfully.");
}else{
Log.v("vii", "Video saving failed. Source file missing.");
}
} catch (Exception e) {
e.printStackTrace();
}
}
public String getPath(Uri uri) {
String[] projection = { MediaStore.Video.Media.DATA };
Cursor cursor = getContentResolver().query(uri, projection, null, null,
null);
if (cursor != null) {
// HERE YOU WILL GET A NULLPOINTER IF CURSOR IS NULL
// THIS CAN BE, IF YOU USED OI FILE MANAGER FOR PICKING THE MEDIA
int column_index = cursor
.getColumnIndexOrThrow(MediaStore.Video.Media.DATA);
cursor.moveToFirst();
return cursor.getString(column_index);
} else
return null;
}
}
【问题讨论】：
标签： java android android-recyclerview android-cardview linearlayoutmanager