Android manifest.xml问题

Question

Following this: http://developer.android.com/training/basics/firstapp/starting-activity.html I am confused when editing the Android Manifest.xml file. It says that the file should contain this:

<application ... >
    <activity android:name="com.example.myapp.DisplayMessageActivity" />
     ...
    </application>

My android manifest.xml looks like this:

    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.nick.myfirstapp"
        android:versionCode="1"
        android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="4"
        android:targetSdkVersion="15" />

    <application android:label="@string/app_name">
       <activity android:name="com.nick.myfirstapp.DisplayMessageActivity" />
        ...
    </application>



</manifest>

and when I run the app everything goes fine except it says : "No Launcher activity found! The launch will only sync the application package on the device!" Is this something missing from the android manifest.xml file?

Answer 1

declare Your Activity in AndroidManifest.xml as for Showing In Launcher as:

<application android:label="@string/app_name">
       <activity android:name="com.nick.myfirstapp.DisplayMessageActivity" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />

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

see for more info how we set an activity which so in Launcher :

http://developer.android.com/reference/android/content/Intent.html

http://developer.android.com/reference/android/app/Activity.html

Answer 2

You need to change you manifest to the following. Doing this will tell Android that you want this Activity to be displayed in the Launcher using your icon.

<application android:label="@string/app_name" android:icon="drawable icon resource here">
       <activity android:name="com.nick.myfirstapp.DisplayMessageActivity" android:label="Your Label">
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />

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

In the docs the used ... to show that your normal code goes here. What you're doing is fine for non-launcher Activities.

Answer 3

You are missing the launcher intent and therefore the app finds no activity to launch at the start.

You need to lay out the activity like so:

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

Answer 4

package="com.example.myfirstapp"

android:versionCode="1"

android:versionName="1.0" >


<uses-sdk

    android:minSdkVersion="8"

    android:targetSdkVersion="17" />


<application

    android:allowBackup="true"

    android:icon="@drawable/ic_launcher"

    android:label="@string/app_name"

    android:theme="@style/AppTheme" >

    <activity

        android:name="com.example.myfirstapp.DisplayMessageActivity"

        android:label="@string/app_name" >

        <intent-filter>

            <action android:name="android.intent.action.MAIN" />


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

        </intent-filter>

    </activity>

</application>