意向不開始活動（將對一項活動有效，而對另一項無效）

Question

我有兩個活動：MainActivity和MenuActivity。 如果我嘗試在SplashActivity之后啟動MainActivity，則可以正常工作，但是如果我嘗試使用MenuActivity進行相同操作，則會給我一個錯誤，我在做什么錯？

表現：

        <activity
            android:name=".SplashActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity
            android:name=".MenuActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MENUACTIVITY" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>

        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAINACTIVITY" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>

SplashActivity.java：

    public class SplashActivity extends Activity{


        @Override
        protected void onCreate(Bundle savedInstanceState) {
            // TODO Auto-generated method stub

            Thread timer = new Thread(){
                public void run (){
                    try {
                        Thread.sleep(5000);
                    } catch(Exception e){
                    } finally {
                        Intent openMenuActivity = new Intent("android.intent.action.MAINACTIVITY");
//THIS WORKS FINE
//HOWEVER,
//Intent openMenuActivity = new Intent("android.intent.action.MENUACTIVITY");
//THIS DOESN'T, WHY?
                        startActivity(openMenuActivity);
                    }

                }
            };

            super.onCreate(savedInstanceState);
            setContentView(R.layout.layout_splashactivity);
            timer.start();  
        }

}

MenuActivity.java：

package com.test.test1;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;

public class MenuActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.layout_menuactivity);


    }
}

MenuButtonView.java：

package com.test.test1;

import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.view.View;

public class MenuButtonView extends View{


    public MenuButtonView(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
    }
    public MenuButtonView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MenuButtonView(Context context, AttributeSet attrs, int in) {
        super(context, attrs, in);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        // TODO Auto-generated method stub
        super.onDraw(canvas);       
    }
}

layout_menuactivity.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <com.test.test1.MenuButtonView
        android:id="@+id/menubuttonview"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight=".7"
        android:layout_gravity="bottom" />

    <com.test.test1.MenuLogoView
        android:id="@+id/menulogoview"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight=".3"
        android:layout_gravity="top" />

</LinearLayout>

LOGCAT：

08-22 04:01:21.649: E/AndroidRuntime(274): FATAL EXCEPTION: main
08-22 04:01:21.649: E/AndroidRuntime(274): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.test.test1/com.test.test1.MenuActivity}: android.view.InflateException: Binary XML file line #14: Error inflating class com.test.test1.MenuLogoView
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.os.Handler.dispatchMessage(Handler.java:99)
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.os.Looper.loop(Looper.java:123)
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.app.ActivityThread.main(ActivityThread.java:4627)
08-22 04:01:21.649: E/AndroidRuntime(274):  at java.lang.reflect.Method.invokeNative(Native Method)
08-22 04:01:21.649: E/AndroidRuntime(274):  at java.lang.reflect.Method.invoke(Method.java:521)
08-22 04:01:21.649: E/AndroidRuntime(274):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-22 04:01:21.649: E/AndroidRuntime(274):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-22 04:01:21.649: E/AndroidRuntime(274):  at dalvik.system.NativeStart.main(Native Method)
08-22 04:01:21.649: E/AndroidRuntime(274): Caused by: android.view.InflateException: Binary XML file line #14: Error inflating class com.test.test1.MenuLogoView
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.view.LayoutInflater.createView(LayoutInflater.java:503)
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:565)
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.view.LayoutInflater.rInflate(LayoutInflater.java:618)
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.view.LayoutInflater.inflate(LayoutInflater.java:407)
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.view.LayoutInflater.inflate(LayoutInflater.java:320)
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.view.LayoutInflater.inflate(LayoutInflater.java:276)
08-22 04:01:21.649: E/AndroidRuntime(274):  at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:198)
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.app.Activity.setContentView(Activity.java:1647)
08-22 04:01:21.649: E/AndroidRuntime(274):  at com.test.test1.MenuActivity.onCreate(MenuActivity.java:12)
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
08-22 04:01:21.649: E/AndroidRuntime(274):  ... 11 more
08-22 04:01:21.649: E/AndroidRuntime(274): Caused by: java.lang.NoSuchMethodException: MenuLogoView(Context,AttributeSet)
08-22 04:01:21.649: E/AndroidRuntime(274):  at java.lang.Class.getMatchingConstructor(Class.java:660)
08-22 04:01:21.649: E/AndroidRuntime(274):  at java.lang.Class.getConstructor(Class.java:477)
08-22 04:01:21.649: E/AndroidRuntime(274):  at android.view.LayoutInflater.createView(LayoutInflater.java:475)
08-22 04:01:21.649: E/AndroidRuntime(274):  ... 21 more

Answer 1

該錯誤表明您需要為MenuButtonView創建構造函數，以xml形式使用的自定義視圖必須實現三個默認構造函數：

確保在MenuButtonView類中具有此構造函數

MenuButtonView(Context context,AttributeSet attrs)
MenuButtonView(Context context)
MenuButtonView(Context context, AttributeSet attrs, int defStyleAttr)

Answer 2

您的layout_menuactivity.xml文件中有錯誤。 您正在引用MenuActivity類的某些方法，該方法尚未在該類中實現。 所以它的拋出錯誤。 一次檢查您的布局文件。

Answer 3

檢查您的R.layout.layout_menuactivity布局。 我認為問題在那里。

您使用了沒有結構的自定義視圖名稱MenuLogoView 。

創建如下結構：

MenuButtonView(Context context,AttributeSet attr)