ActivityManager：警告：活動尚未開始，其當前任務已被帶到最前面繼續彈出？

Question

我是Android開發工具世界的新手，我剛剛在筆記本電腦上下載了Eclipse和ADT插件。 我只是按照我在網上觀看的視頻教程制作了一個按鈕，但在模擬器上無法使用，因此我嘗試將android手機連接到筆記本電腦並下載了所需的驅動程序。 在android設備上，程序包本身會彈出，但是我做的按鈕不會彈出。 訊息

ActivityManager：警告：活動尚未開始，其當前任務已被置於最前面

說完以下所有內容后，總是會在控制台上彈出：

Android Launch! 
[2014-07-24 08:22:11 - PLEASEBUTTON] adb is running normally. 
[2014-07-24 08:22:11 - PLEASEBUTTON] Performing com.example.pleasebutton.MainActivity activity launch 
[2014-07-24 08:22:13 - PLEASEBUTTON] Application already deployed. No need to reinstall. 
[2014-07-24 08:22:13 - PLEASEBUTTON] Starting activity com.example.pleasebutton.MainActivity on device 3934C3A970FE00EC 
[2014-07-24 08:22:13 - PLEASEBUTTON] ActivityManager: Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] cmp=com.example.pleasebutton/.MainActivity } 
[2014-07-24 08:22:14 - PLEASEBUTTON] ActivityManager: Warning: Activity not started, its current task has been brought to the front

我仍然不知道發生了什么，我真的想解決這個問題。

package com.example.pleasebutton;

import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.os.Build;
import android.app.Activity;
import android.view.View;
import android.widget.Toast;


public class MainActivity extends Activity implements View.OnClickListener{

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


 }
 public void onClick(View v){}   
 public void buttonBtn (View v) {
     Toast.makeText(this,"You just pressed a button",Toast.LENGTH_LONG).show();

 }
}

這是活動xml文件

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.pleasebutton.MainActivity"
tools:ignore="MergeRootFrame" />

這是片段xml文件

<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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.pleasebutton.MainActivity$PlaceholderFragment" >

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/hello_world" />

<Button
    android:id="@+id/awesomebutton"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:onClick="buttonBtn"
    android:text="Cool Button" />

Answer 1

試試這個代碼：

public class MainActivity extends Activity {

    private Button bAfficher;


    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        // Assign graphical button to attribute

        bAfficher = (Button) this.findViewById(R.id.awesomebutton);



        bAfficher.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {

                 Toast.makeText(this,"You just pressed a button",Toast.LENGTH_LONG).show();

 }
});
}
}