问题
I want to create a GridLayout able to run in all the APIs.
The thing is, when i use GridLayout instead of android.support.v7.widget.GridLayout the app runs fine in Android 7.1.1 but in older versions it crashes.
But if i use android.support.v7.widget.GridLayout instead of GridLayout (like the code below) it always crashes.
activity_main
<?xml version="1.0" encoding="utf-8"?>
<ScrollView 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"
android:background="#FFF"
tools:context="devector.dom.gridtest.MainActivity">
<LinearLayout
android:layout_width="match_parent"
android:orientation="vertical"
android:layout_height="wrap_content">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/textGrid"
android:text="Grid test"
android:textColor="#000"
android:layout_centerInParent="true"
android:textSize="34sp"
/>
</RelativeLayout>
<android.support.v7.widget.GridLayout
android:textAlignment="center"
android:id="@+id/mainGrid"
android:padding="25dp"
android:layout_marginLeft="8dp"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:columnCount="2"
app:rowCount="3"
app:alignmentMode="alignMargins"
app:columnOrderPreserved="false">
<!-- Row 1 -->
<!-- Column 1-->
<android.support.v7.widget.CardView
android:layout_width="150dp"
android:layout_height="125dp"
android:layout_marginBottom="16dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
app:cardElevation="8dp"
app:cardCornerRadius="8dp"
>
<LinearLayout
android:layout_gravity="center_horizontal|center_vertical"
android:layout_margin="16dp"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
>
<ImageView
android:src="@drawable/zerotwo"
android:layout_gravity="center_horizontal"
android:layout_width="70dp"
android:layout_height="70dp"
/>
<TextView
android:text="Zero"
android:textAlignment="center"
android:textColor="#000"
android:textSize="18sp"
android:textStyle="bold"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v7.widget.CardView>
<!-- Row 2 -->
<!-- Column 2-->
<android.support.v7.widget.CardView
android:layout_width="150dp"
android:layout_height="125dp"
android:layout_marginBottom="16dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
app:cardElevation="8dp"
app:cardCornerRadius="8dp"
>
<LinearLayout
android:layout_gravity="center_horizontal|center_vertical"
android:layout_margin="16dp"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
>
<ImageView
android:src="@drawable/zerotwo"
android:layout_gravity="center_horizontal"
android:layout_width="70dp"
android:layout_height="70dp"
/>
<TextView
android:text="Two"
android:textAlignment="center"
android:textColor="#000"
android:textSize="18sp"
android:textStyle="bold"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v7.widget.CardView>
<!-- Row 3-->
<!-- Column 3-->
<android.support.v7.widget.CardView
android:layout_width="150dp"
android:layout_height="125dp"
android:layout_marginBottom="16dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
app:cardElevation="8dp"
app:cardCornerRadius="8dp"
>
<LinearLayout
android:layout_gravity="center_horizontal|center_vertical"
android:layout_margin="16dp"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
>
<ImageView
android:src="@drawable/zerotwo"
android:layout_gravity="center_horizontal"
android:layout_width="70dp"
android:layout_height="70dp"
/>
<TextView
android:text="Is"
android:textAlignment="center"
android:textColor="#000"
android:textSize="18sp"
android:textStyle="bold"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v7.widget.CardView>
<!-- Row 4 -->
<!-- Column 4-->
<android.support.v7.widget.CardView
android:layout_width="150dp"
android:layout_height="125dp"
android:layout_marginBottom="16dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
app:cardElevation="8dp"
app:cardCornerRadius="8dp"
>
<LinearLayout
android:layout_gravity="center_horizontal|center_vertical"
android:layout_margin="16dp"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
>
<ImageView
android:src="@drawable/zerotwo"
android:layout_gravity="center_horizontal"
android:layout_width="70dp"
android:layout_height="70dp"
/>
<TextView
android:text="The"
android:textAlignment="center"
android:textColor="#000"
android:textSize="18sp"
android:textStyle="bold"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v7.widget.CardView>
<!-- Row 5 -->
<!-- Column 5-->
<android.support.v7.widget.CardView
android:layout_width="150dp"
android:layout_height="125dp"
android:layout_marginBottom="16dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
app:cardElevation="8dp"
app:cardCornerRadius="8dp"
>
<LinearLayout
android:layout_gravity="center_horizontal|center_vertical"
android:layout_margin="16dp"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
>
<ImageView
android:src="@drawable/zerotwo"
android:layout_gravity="center_horizontal"
android:layout_width="70dp"
android:layout_height="70dp"
/>
<TextView
android:text="Besto"
android:textAlignment="center"
android:textColor="#000"
android:textSize="18sp"
android:textStyle="bold"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v7.widget.CardView>
<!-- Row 6 -->
<!-- Column 6-->
<android.support.v7.widget.CardView
android:layout_width="150dp"
android:layout_height="125dp"
android:layout_marginBottom="16dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
app:cardElevation="8dp"
app:cardCornerRadius="8dp"
>
<LinearLayout
android:layout_gravity="center_horizontal|center_vertical"
android:layout_margin="16dp"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
>
<ImageView
android:src="@drawable/zerotwo"
android:layout_gravity="center_horizontal"
android:layout_width="70dp"
android:layout_height="70dp"
/>
<TextView
android:text="Waifu"
android:textAlignment="center"
android:textColor="#000"
android:textSize="18sp"
android:textStyle="bold"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v7.widget.CardView>
<!-- Row 7 -->
<!-- Column 7-->
<android.support.v7.widget.CardView
android:layout_width="150dp"
android:layout_height="125dp"
android:layout_marginBottom="16dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
app:cardElevation="8dp"
app:cardCornerRadius="8dp"
>
<LinearLayout
android:layout_gravity="center_horizontal|center_vertical"
android:layout_margin="16dp"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
>
<ImageView
android:src="@drawable/zerotwo"
android:layout_gravity="center_horizontal"
android:layout_width="70dp"
android:layout_height="70dp"
/>
<TextView
android:text="Never"
android:textAlignment="center"
android:textColor="#000"
android:textSize="18sp"
android:textStyle="bold"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v7.widget.CardView>
<!-- Row 8 -->
<!-- Column 8-->
<android.support.v7.widget.CardView
android:layout_width="150dp"
android:layout_height="125dp"
android:layout_marginBottom="16dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
app:cardElevation="8dp"
app:cardCornerRadius="8dp"
>
<LinearLayout
android:layout_gravity="center_horizontal|center_vertical"
android:layout_margin="16dp"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
>
<ImageView
android:src="@drawable/zerotwo"
android:layout_gravity="center_horizontal"
android:layout_width="70dp"
android:layout_height="70dp"
/>
<TextView
android:text="Forget"
android:textAlignment="center"
android:textColor="#000"
android:textSize="18sp"
android:textStyle="bold"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v7.widget.CardView>
<!-- Row 9 -->
<!-- Column 9-->
<android.support.v7.widget.CardView
android:layout_width="150dp"
android:layout_height="125dp"
android:layout_marginBottom="16dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
app:cardElevation="8dp"
app:cardCornerRadius="8dp"
>
<LinearLayout
android:layout_gravity="center_horizontal|center_vertical"
android:layout_margin="16dp"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
>
<ImageView
android:src="@drawable/zerotwo"
android:layout_gravity="center_horizontal"
android:layout_width="70dp"
android:layout_height="70dp"
/>
<TextView
android:text="About"
android:textAlignment="center"
android:textColor="#000"
android:textSize="18sp"
android:textStyle="bold"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v7.widget.CardView>
<!-- Row 10 -->
<!-- Column 10-->
<android.support.v7.widget.CardView
android:layout_width="150dp"
android:layout_height="125dp"
android:layout_marginBottom="16dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
app:cardElevation="8dp"
app:cardCornerRadius="8dp"
>
<LinearLayout
android:layout_gravity="center_horizontal|center_vertical"
android:layout_margin="16dp"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
>
<ImageView
android:src="@drawable/zerotwo"
android:layout_gravity="center_horizontal"
android:layout_width="70dp"
android:layout_height="70dp"
/>
<TextView
android:text="It"
android:textAlignment="center"
android:textColor="#000"
android:textSize="18sp"
android:textStyle="bold"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v7.widget.CardView>
</android.support.v7.widget.GridLayout>
</LinearLayout>
</ScrollView>
Logs
FATAL EXCEPTION: main
Process: devector.dom.gridtest, PID: 15773
java.lang.RuntimeException: Unable to start activity ComponentInfo{devector.dom.gridtest/devector.dom.gridtest.MainActivity}: java.lang.ClassCastException: android.support.v7.widget.GridLayout cannot be cast to android.widget.GridLayout
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2678)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2743)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1490)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6165)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:888)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:778)
Caused by: java.lang.ClassCastException: android.support.v7.widget.GridLayout cannot be cast to android.widget.GridLayout
at devector.dom.gridtest.MainActivity.onCreate(MainActivity.java:21)
at android.app.Activity.performCreate(Activity.java:6687)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1140)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2631)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2743)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1490)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6165)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:888)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:778)
Gradle
apply plugin: 'com.android.application'
android {
compileSdkVersion 26
defaultConfig {
applicationId "devector.dom.gridtest"
minSdkVersion 15
targetSdkVersion 26
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:26.1.0'
implementation 'com.android.support:cardview-v7:26.1.0'
implementation 'com.android.support.constraint:constraint-layout:1.0.2'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.1'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
implementation 'com.android.support:gridlayout-v7:26.1.0'
implementation 'com.android.support:design:26.1.0'
}
MainActivity.java
package devector.dom.gridtest;
import android.content.Intent;
import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.CardView;
import android.view.View;
import android.widget.GridLayout;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
GridLayout mainGrid;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mainGrid = (GridLayout) findViewById(R.id.mainGrid);
setSingleEvent(mainGrid);
}
private void setSingleEvent(GridLayout mainGrid) {
for (int i = 0; i < mainGrid.getChildCount(); i++) {
CardView cardView = (CardView) mainGrid.getChildAt(i);
final int finalI = i;
cardView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if(finalI == 0)
{
Intent intent = new Intent(MainActivity.this,Activity_one.class );
startActivity(intent);
}
}
});
}
}
}
回答1:
Yes from your error log ,
android.support.v7.widget.GridLayout cannot be cast to android.widget.GridLayout
at devector.dom.gridtest.MainActivity.onCreate(MainActivity.java:21)
you can change your casting like this way to solve your problem
android.support.v7.widget.GridLayout grid = (android.support.v7.widget.GridLayout)findViewById(R.id.grid);
回答2:
Replace
'import android.widget.GridLayout;'
by
'import android.support.v7.widget.GridLayout;'
This worked for me . Hope this will work for you.......
回答3:
Caused by: java.lang.ClassCastException: android.support.v7.widget.GridLayout cannot be cast to android.widget.GridLayout at devector.dom.gridtest.MainActivity.onCreate(MainActivity.java:21)
=> From this line, it's clear that you must be importing and referring to android.widget.GridLayout where as you have taken android.support.v7.widget.GridLayout in XML layout. Use and refer either of any in both layout and class file.
回答4:
I had the same issue and I just go to activity_main.xml and replaced
android.support.v7.widget.GridLayout
to this:
android.widget.GridLayout
回答5:
I got the same issue. I solved it by using the GridLayout from package android.support.v7.widget.GridLayout, since I was previously using the android.widget.GridLayout package which gave me the error.
回答6:
Just change the format a little bit: androidx.gridlayout.widget.GridLayout newGrid= (androidx.gridlayout.widget.GridLayout) findViewById (R.id.yourGrid);
来源：https://stackoverflow.com/questions/48760862/android-gridlayout-android-support-v7-widget-gridlayout-cannot-be-cast-to-andr