I'm trying to call setText()
method of a TextView
frequently to display time on a second thread. The TextView
is a part of a layout which added programmatically to the MainActivity's root view. The app crashes when I try to call setText()
due to the error.
NullPointerException: Attempt to invoke virtual method on a null object reference
I have tried accessing the TextView
with different approaches, but every time it threw the same NullPointerException
. The only solution that I know is to add the layout I want to the activity_main.xml, but that's not quite what I want.
Here's how I inflate and add the views to a Linearlayout(id/WidgetScreen) inside the MainActivity.java and how I'm calling the setText()
method.
´´´ LinearLayout WidgetScreen = (LinearLayout) findViewById(R.id.WidgetScreen);
mTime = getLayoutInflater().inflate(R.layout.widget_time, null);
mDate = (TextView) mTime.findViewById(R.id.TVdate);
mMEZ = (TextView) mTime.findViewById(R.id.TVmez);
mGMT = (TextView) mTime.findViewById(R.id.TVgmt);
WidgetScreen.addView(mTime);
// The code where I set time for TextView
while (!StopDateThread) {
final String mmTime = getformatedUST();
final String mmDate = getformatedDate();
final String mmGMT = getformatedGMT();
Log.d(TAG, "run: ");
try {
mMEZ.setText(mmTime);
mDate.setText(mmDate);
mGMT.setText(mmGMT);
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
widget_time.XML
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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:orientation="vertical"
android:layout_width="match_parent"
android:id="@+id/WidgetTabTime"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/ic_clock"
android:layout_marginTop="@dimen/LabelIconMarginTop"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintStart_toStartOf="parent"
android:layout_marginStart="@dimen/LabelIconMarginStart"
android:layout_gravity="center"
android:contentDescription="CLOCK"
android:id="@+id/LabelIcon"/>
<View
android:id="@+id/view"
android:layout_width="match_parent"
android:layout_height="@dimen/StrokeWidth"
android:layout_marginTop="@dimen/LabelDividerMarginTop"
android:background="@color/colorAccent"
app:layout_constraintTop_toBottomOf="@id/LabelIcon" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="@color/colorAccent"
android:fontFamily="sans-serif-light"
app:layout_constraintStart_toEndOf="@id/LabelIcon"
android:layout_marginStart="@dimen/LabelTextMarginStart"
app:layout_constraintBottom_toBottomOf="@id/LabelIcon"
android:text="@string/time"
android:textSize="@dimen/LabelText"/>
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Date:"
app:layout_constraintStart_toStartOf="parent"
android:layout_marginStart="@dimen/StatsMarginStart"
android:layout_marginTop="@dimen/StatsMarginTop"
android:textColor="@color/colorAccent"
android:fontFamily="sans-serif-light"
android:textSize="@dimen/StatsText"
app:layout_constraintTop_toBottomOf="@+id/view" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="@dimen/StatsMarginTop"
android:fontFamily="sans-serif-light"
android:text="MEZ:"
android:textColor="@color/colorAccent"
android:textSize="@dimen/StatsText"
app:layout_constraintStart_toStartOf="@+id/textView"
app:layout_constraintTop_toBottomOf="@+id/textView" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="GMT:"
android:textColor="@color/colorAccent"
android:fontFamily="sans-serif-light"
android:textSize="@dimen/StatsText"
android:layout_marginTop="@dimen/StatsMarginTop"
app:layout_constraintStart_toStartOf="@+id/textView2"
app:layout_constraintTop_toBottomOf="@+id/textView2" />
<TextView
android:id="@+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="LST:"
android:layout_marginTop="@dimen/StatsMarginTop"
android:textColor="@color/colorAccent"
android:fontFamily="sans-serif-light"
android:textSize="@dimen/StatsText"
app:layout_constraintStart_toStartOf="@+id/textView3"
app:layout_constraintTop_toBottomOf="@+id/textView3" />
<TextView
android:id="@+id/TVdate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/CurrentDate"
android:layout_marginEnd="@dimen/StatsMarginEnd"
android:textColor="@color/colorAccent"
android:fontFamily="sans-serif-light"
android:textSize="@dimen/StatsText"
app:layout_constraintBottom_toBottomOf="@+id/textView"
app:layout_constraintEnd_toEndOf="parent" />
<TextView
android:id="@+id/TVmez"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/CurrentLocalTime"
android:layout_marginEnd="@dimen/StatsMarginEnd"
android:textColor="@color/colorAccent"
android:fontFamily="sans-serif-light"
android:textSize="@dimen/StatsText"
app:layout_constraintBottom_toBottomOf="@+id/textView2"
app:layout_constraintEnd_toEndOf="parent" />
<TextView
android:id="@+id/TVgmt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/CurrentGMT"
android:layout_marginEnd="@dimen/StatsMarginEnd"
android:textColor="@color/colorAccent"
android:fontFamily="sans-serif-light"
android:textSize="@dimen/StatsText"
app:layout_constraintBottom_toBottomOf="@+id/textView3"
app:layout_constraintEnd_toEndOf="parent" />
<TextView
android:id="@+id/textView8"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="02:57:15"
android:layout_marginEnd="@dimen/StatsMarginEnd"
android:textColor="@color/colorAccent"
android:fontFamily="sans-serif-light"
android:textSize="@dimen/StatsText"
app:layout_constraintBottom_toBottomOf="@+id/textView4"
app:layout_constraintEnd_toEndOf="parent" />
<View
android:layout_width="match_parent"
android:layout_height="5dp"
app:layout_constraintTop_toBottomOf="@id/textView4"/>
<View
android:layout_width="match_parent"
android:layout_height="5dp"
app:layout_constraintTop_toBottomOf="@id/textView4"/>
</androidx.constraintlayout.widget.ConstraintLayout>
What would be the simplest way to access the setText()
method?
you can't use findViewById()
on inflated layout you must add the inflated layout to your main layout via
mainLayout.addView(mTime);
as written here findViewById() returns null for an inflated layout
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.