Android意圖應用程序崩潰

Question

我正在嘗試爲一個項目創建一個非常小的應用程序。我有兩個按鈕以隱含的意圖調用應用程序，但無論何時按下，應用程序（我創建的那個）都會一直崩潰。這是怎麼回事？下面的代碼：

package com.messengerassist; 

import android.content.Intent; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 

public class MainActivity extends AppCompatActivity { 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
    } 
    public void startPostmates() { 
     Intent launchIntent = getPackageManager().getLaunchIntentForPackage("com.postmates.android.courier"); 
     startActivity(launchIntent); 
    } 
    public void startCaviar() { 
     Intent launchIntent = getPackageManager().getLaunchIntentForPackage("com.trycaviar.courier"); 
     startActivity(launchIntent); 
    } 
} 

然後

activity_main.xml中：

<?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" 
    android:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    android:paddingBottom="@dimen/activity_vertical_margin" 
    tools:context="com.messengerassist.MainActivity"> 

    <Button 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="Start Postmates" 
     android:id="@+id/startPostmates" 
     android:onClick="startPostmates" 
     android:layout_alignParentTop="true" 
     android:layout_centerHorizontal="true" /> 

    <Button 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="Start Caviar" 
     android:id="@+id/startCaviar" 
     android:onClick="Start Caviar" 
     android:layout_below="@+id/startPostmates" 
     android:layout_centerHorizontal="true" /> 
</RelativeLayout> 

這裏是logcat的是給我：

12-21 20:10:28.919 4108-4108/com.messengerassist E/AndroidRuntime: FATAL EXCEPTION: main 
                    Process: com.messengerassist, PID: 4108 
                    java.lang.IllegalStateException: Could not find method startPostmates(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatButton with id 'startPostmates' 
                     at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:307) 
                     at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:266) 
                     at android.view.View.performClick(View.java:4789) 
                     at android.view.View$PerformClick.run(View.java:19881) 
                     at android.os.Handler.handleCallback(Handler.java:739) 
                     at android.os.Handler.dispatchMessage(Handler.java:95) 
                     at android.os.Looper.loop(Looper.java:135) 
                     at android.app.ActivityThread.main(ActivityThread.java:5292) 
                     at java.lang.reflect.Method.invoke(Native Method) 
                     at java.lang.reflect.Method.invoke(Method.java:372) 
                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904) 
                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699) 

Answer 1

當您註冊一個點擊監聽方法在你的XML中，該方法應該將View作爲參數。從logcat改變像這樣的方法簽名可以解決問題

public void startPostmates(View view) { ...} 
public void startCaviar(View view) {...}