[英]Android - how to auto scroll textView to align with editText position?
I am trying to create a notepad with the line number.我正在尝试使用行号创建一个记事本。 I am able to display lineNumber
but the problem is that as soon as editext
reaches the end of the screen textview is not getting auto-scroll with editext current position
or lineNumber
.我能够显示lineNumber
但问题是,一旦editext
到达屏幕的末尾, textview 就不会自动滚动editext current position
或lineNumber
。
Here is XML Code这是 XML 代码
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/lineNumber"
android:layout_width="40dp"
android:layout_height="match_parent"
android:background="#eee"
android:gravity="center_horizontal"
android:padding="10dp"
android:text="1"
android:textSize="18sp"
tools:layout_editor_absoluteY="12dp"
/>
<EditText
android:id="@+id/fileText"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_toEndOf="@+id/lineNumber"
android:ems="10"
android:padding="10dp"
android:gravity="left|top"
android:inputType="textMultiLine"
android:scrollbars="vertical"/>
</RelativeLayout>
Here is Fragment Code这是片段代码
public class FileViewFragment extends Fragment {
TextView lineNumber;
EditText fileText;
String fileName = "";
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_file_viewer, container, false);
lineNumber = view.findViewById(R.id.lineNumber);
fileText = view.findViewById(R.id.fileText);
fileText.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
int lines = fileText.getLineCount();
String linesNumber = "";
for (int i = 1; i <= lines; i++) {
linesNumber = linesNumber + i + "\n";
}
lineNumber.setText(linesNumber);
}
@Override
public void afterTextChanged(Editable s) {
}
});
return view;
}
}
So, how can I auto-scroll textview with editext position?那么,如何使用 editext 位置自动滚动 textview?
In your onTextChanged method after you have set the new lineNumber Text you have to calculate the current Y position of your EditText and scroll the TextView to that position by using its scrollTo method.在设置新 lineNumber Text 后的onTextChanged方法中,您必须计算 EditText 的当前 Y 位置并使用其scrollTo方法将 TextView 滚动到该位置。 The calculation of EditText Y position will be like below: EditText Y 位置的计算如下:
int y = fileText.getLayout().getLineTop(fileText.getLineCount()) - (fileText.getHeight()) + (fileText.getPaddingBottom()) + (fileText.getPaddingTop());
lineNumber.scrollTo(0, Math.max(y, 0));
and of course if you want the TextView to be scrollable you have to add the below line of code in your onCreateView method:当然,如果您希望 TextView 可滚动,则必须在onCreateView方法中添加以下代码行:
lineNumber.setMovementMethod(new ScrollingMovementMethod());
To solve the scrolling issue you have to change your xml file and put both EditText and TextView in a single parent View wrapping to its content which is inside a scrollview, so now the whole view will be scrollable.要解决滚动问题,您必须更改您的 xml 文件并将 EditText 和 TextView 放在单个父视图中,并包装到滚动视图内的内容,因此现在整个视图都将是可滚动的。 Below is the new xml file:下面是新的 xml 文件:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:layout_width="40dp"
android:layout_height="match_parent"
android:layout_alignParentStart="true"
android:background="#eee"/>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:id="@+id/containerRl"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="@+id/lineNumber"
android:layout_width="40dp"
android:layout_height="match_parent"
android:background="#eee"
android:gravity="center_horizontal"
android:padding="10dp"
android:text="1"
android:textSize="18sp"
tools:layout_editor_absoluteY="12dp" />
<EditText
android:id="@+id/fileText"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_toEndOf="@+id/lineNumber"
android:ems="10"
android:padding="10dp"
android:gravity="left|top"
android:inputType="textMultiLine"
android:scrollbars="vertical"/>
</RelativeLayout>
</ScrollView>
</RelativeLayout>
And remove the lines of code in my previous answer.并删除我之前的答案中的代码行。
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