Question

我创建了一个包含网格布局和线性布局的项目。网格布局中有一些ImageView。首先，我将线性布局设置为不可见，并将网格布局设置为可见。在这些ImageViews下，添加onClick方法。当我单击这些图像时，onClick方法会将网格布局更改为不可见，而将线性布局更改为可见。因此线性布局出现了，网格布局消失了。但是，每次将网格布局更改为不可见时，App崩溃并给我一个例外：

ClassNotFoundException: Didn't find class 
"android.view.View$OnUnhandledKeyEventListener"

但可以将线性布局更改为可见。

我已经搜索过Google并检查了我的代码，但找不到任何问题。

我一步一步检查，发现崩溃仅是由于将网格布局更改为不可见而引起的。我还创建了一个新的简单项目对其进行测试，但仍然存在此问题。

GridLayout mainLayout = (GridLayout)findViewById(R.id.gridLayout);
mainLayout.setVisibility(View.INVISIBLE);
LinearLayout winnerLayout = 
(LinearLayout)findViewById(R.id.winnerLayout);
winnerLayout.setVisibility(View.VISIBLE);

XML：

?xml version="1.0" encoding="utf-8"?>
<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"
tools:context=".MainActivity">

<android.support.v7.widget.GridLayout
    android:id="@+id/gridLayout"
    android:layout_width="0dp"
    android:layout_height="413dp"
    android:background="@drawable/board"
    android:visibility="visible"
    app:columnCount="3"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintDimensionRatio="w,1:1"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:rowCount="3"
   >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="134dp"
        android:layout_height="125dp"
        android:layout_marginTop="0dp"
        android:onClick="dropIn"
        android:scaleType="fitCenter"
        android:tag="0"
        app:layout_column="0"
        app:layout_row="0"
        tools:layout_editor_absoluteX="180dp"
        tools:layout_editor_absoluteY="162dp" />

    <ImageView
        android:id="@+id/imageView2"
        android:layout_width="134dp"
        android:layout_height="125dp"
        android:layout_marginLeft="7dp"
        android:onClick="dropIn"
        android:scaleType="fitCenter"
        android:tag="1"
        app:layout_column="1"
        app:layout_row="0"
        tools:layout_editor_absoluteX="180dp"
        tools:layout_editor_absoluteY="162dp" />

    <ImageView
        android:id="@+id/imageView3"
        android:layout_width="134dp"
        android:layout_height="125dp"
        android:layout_marginLeft="4dp"
        android:onClick="dropIn"
        android:scaleType="fitCenter"
        android:tag="2"
        app:layout_column="2"
        app:layout_row="0"
        tools:layout_editor_absoluteX="180dp"
        tools:layout_editor_absoluteY="162dp" />

    <ImageView
        android:id="@+id/imageView4"
        android:layout_width="134dp"
        android:layout_height="125dp"
        android:layout_marginTop="20dp"
        android:onClick="dropIn"
        android:scaleType="fitCenter"
        android:tag="3"
        app:layout_column="0"
        app:layout_row="1"
        tools:layout_editor_absoluteX="180dp"
        tools:layout_editor_absoluteY="162dp" />

    <ImageView
        android:id="@+id/imageView5"
        android:layout_width="134dp"
        android:layout_height="125dp"
        android:layout_marginLeft="7dp"
        android:layout_marginTop="20dp"
        android:onClick="dropIn"
        android:scaleType="fitCenter"
        android:tag="4"
        app:layout_column="1"
        app:layout_row="1"
        tools:layout_editor_absoluteX="180dp"
        tools:layout_editor_absoluteY="162dp" />

    <ImageView
        android:id="@+id/imageView6"
        android:layout_width="134dp"
        android:layout_height="125dp"
        android:layout_marginLeft="4dp"
        android:layout_marginTop="20dp"
        android:onClick="dropIn"
        android:scaleType="fitCenter"
        android:tag="5"
        app:layout_column="2"
        app:layout_row="1"
        tools:layout_editor_absoluteX="180dp"
        tools:layout_editor_absoluteY="162dp" />

    <ImageView
        android:id="@+id/imageView7"
        android:layout_width="134dp"
        android:layout_height="125dp"
        android:layout_marginTop="15dp"
        android:onClick="dropIn"
        android:scaleType="fitCenter"
        android:tag="6"
        app:layout_column="0"
        app:layout_row="2"
        tools:layout_editor_absoluteX="180dp"
        tools:layout_editor_absoluteY="162dp" />

    <ImageView
        android:id="@+id/imageView8"
        android:layout_width="134dp"
        android:layout_height="125dp"
        android:layout_marginLeft="7dp"
        android:layout_marginTop="15dp"
        android:onClick="dropIn"
        android:scaleType="fitCenter"
        android:tag="7"
        app:layout_column="1"
        app:layout_row="2"
        tools:layout_editor_absoluteX="180dp"
        tools:layout_editor_absoluteY="162dp" />

    <ImageView
        android:id="@+id/imageView9"
        android:layout_width="134dp"
        android:layout_height="125dp"
        android:layout_marginLeft="4dp"
        android:layout_marginTop="15dp"
        android:onClick="dropIn"
        android:scaleType="fitCenter"
        android:tag="8"
        app:layout_column="2"
        app:layout_row="2"
        tools:layout_editor_absoluteX="180dp"
        tools:layout_editor_absoluteY="162dp" />

</android.support.v7.widget.GridLayout>

<LinearLayout
    android:id="@+id/winnerLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:orientation="vertical"
    android:visibility="invisible"
    >

    <TextView
        android:id="@+id/winnerText"
        android:layout_width="310dp"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        android:fontFamily="@font/finger_paint"
        android:gravity="center"
        android:text="Yellow Won"
        android:textAlignment="center"
        android:textColor="@android:color/holo_red_light"
        android:textSize="70sp"
        android:typeface="monospace"
        tools:layout_editor_absoluteY="222dp" />


</LinearLayout>
</android.support.constraint.ConstraintLayout>

Logcat：

--------- beginning of crash
2019-01-28 12:05:15.704 5002-5002/sailorsinbad.com.udemy5_clock_rotation 
E/AndroidRuntime: FATAL EXCEPTION: main
Process: sailorsinbad.com.udemy5_clock_rotation, PID: 5002
java.lang.IllegalStateException: Could not execute method for 
android:onClick
    at 
android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick( 
AppCompatViewInflater.java:389)
    at android.view.View.performClick(View.java:6294)
    at android.view.View$PerformClick.run(View.java:24770)
    at android.os.Handler.handleCallback(Handler.java:790)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:164)
    at android.app.ActivityThread.main(ActivityThread.java:6494)
    at java.lang.reflect.Method.invoke(Native Method)
    at 
 com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java: 
 438)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
 Caused by: java.lang.reflect.InvocationTargetException
    at java.lang.reflect.Method.invoke(Native Method)
    at 
android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick( 
AppCompatViewInflater.java:384)
    at android.view.View.performClick(View.java:6294) 
    at android.view.View$PerformClick.run(View.java:24770) 
    at android.os.Handler.handleCallback(Handler.java:790) 
    at android.os.Handler.dispatchMessage(Handler.java:99) 
    at android.os.Looper.loop(Looper.java:164) 
    at android.app.ActivityThread.main(ActivityThread.java:6494) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807) 
 Caused by: java.lang.ClassCastException: android.support.v7.widget.GridLayout cannot be cast to android.widget.GridLayout
    at sailorsinbad.com.udemy5_clock_rotation.MainActivity.resetAndNextGame(MainActivity.java:36)
    at sailorsinbad.com.udemy5_clock_rotation.MainActivity.dropIn(MainActivity.java:72)
    at java.lang.reflect.Method.invoke(Native Method) 
    at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:384) 
    at android.view.View.performClick(View.java:6294) 
    at android.view.View$PerformClick.run(View.java:24770) 
    at android.os.Handler.handleCallback(Handler.java:790) 
    at android.os.Handler.dispatchMessage(Handler.java:99) 
    at android.os.Looper.loop(Looper.java:164) 
    at android.app.ActivityThread.main(ActivityThread.java:6494) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807) 


--------- beginning of system

Design View

Code

更新

我点击此链接（android/view/view$onUnhandledKeyEventListener (onMeasure error)），将sdk从28更改为27：

compileSdkVersion 27

targetSdkVersion 27

implementation 'com.android.support:appcompat-v7:27.1.1'

我同步了Gradle并运行它，但仍然崩溃。我的MainActivity代码：

package sailorsinbad.com.udemy5_clock_rotation;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.GridLayout;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;


public class MainActivity extends AppCompatActivity {
boolean winningState = false;
int isRed = 1;
//red is 1; yellow is 2
int[] gameState = {0,0,0,0,0,0,0,0,0};
int[][] winningCondition = {
        {0,1,2}, {3,4,5}, {6,7,8},
        {0,3,6}, {1,4,7}, {2,5,8},
        {0,4,8}, {2,4,6}
    };
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


}

public void animationDropIn(View drop) {
    drop.setTranslationY(-1000f);
    drop.animate().translationYBy(1000f).rotation(720).setDuration(250);
}
public void resetAndNextGame(String winner){
    //switch to winner layout
    GridLayout mainLayout = (GridLayout)findViewById(R.id.gridLayout);
    mainLayout.setVisibility(View.INVISIBLE);
    LinearLayout winnerLayout = 
    (LinearLayout)findViewById(R.id.winnerLayout);
    winnerLayout.setVisibility(View.VISIBLE);
    TextView text = (TextView)findViewById(R.id.winnerText);
    text.setText(winner);
}
public void dropIn(View view) {
    //catch current rectangle building block area (View)
    ImageView drop = (ImageView) view;
    //drop-in animation
    //2 sides cross drop in, prevent repeat drop, record game state
    int tagNum= Integer.parseInt(drop.getTag().toString());
    //System.out.println(tagNum);
    if (!winningState) {
        if (isRed == 1 && gameState[tagNum] == 0) {
            drop.setImageResource(R.drawable.red);
            gameState[tagNum] = isRed;
            animationDropIn(drop);
            isRed = 2;

        } else if (isRed == 2 && gameState[tagNum] == 0) {
            drop.setImageResource(R.drawable.yellow);
            gameState[tagNum] = isRed;
            animationDropIn(drop);
            isRed = 1;
        }
        // System.out.println(gameState[tagNum]);
        //game checking winning condition
        for (int[] winniningPosition : winningCondition) {
            if (gameState[winniningPosition[0]] == 
                gameState[winniningPosition[1]]
                    && gameState[winniningPosition[1]] == 
                gameState[winniningPosition[2]] && 
                gameState[winniningPosition[0]] != 0) {
                if (isRed == 2) {
                    //reversed before
                    String win = "Red Win";
                    winningState = true;
                    resetAndNextGame(win);
                } else {
                    String win = "Yellow Win";
                    winningState = true;
                     resetAndNextGame(win);
                }
            } else {
                boolean isGameOver = true;
                for (int counter : gameState) {
                    if (counter == 0) {
                        isGameOver = false;
                    }
                }
                if (isGameOver) {
                    String win = "Draw";
                    winningState = true;
                     resetAndNextGame(win);
                }

            }

        }
    }
}
}

我的构建。Gradle：

apply plugin: 'com.android.application'

android {
compileSdkVersion 27
defaultConfig {
    applicationId "sailorsinbad.com.udemy5_clock_rotation"
    minSdkVersion 21
    targetSdkVersion 27
    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 'com.android.support:appcompat-v7:27.1.1'
implementation fileTree(dir: 'libs', include: ['*.jar'])

implementation 'com.android.support.constraint:constraint-layout:1.1.3'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso- 
core:3.0.2'
implementation 'com.android.support:gridlayout-v7:27.1.1'
}

Answer 1

您的MainActivity import android.widget.GridLayout;中的导入错误。

您需要使用import android.support.v7.widget.GridLayout，因为您要在xml文件中夸大GridLayout的支持库版本。

查看崩溃原因-Caused by: java.lang.ClassCastException: android.support.v7.widget.GridLayout cannot be cast to android.widget.GridLayout

当我将布局更改为不可见时，如何修复ClassNotFoundException

1 个答案: