解决：Caused by: android.content.res.Resources$NotFoundException: String resource ID #0x2

Posted 2021-01-23 一只假喵

　　在运行android app时出现以下错误：

   --------- beginning of crash
11-28 07:53:56.485 6712-6712/com.trojane.android.learnactivity E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.trojane.android.learnactivity, PID: 6712
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.trojane.android.learnactivity/com.trojane.android.learnactivity.SecondActivity}: android.content.res.Resources$NotFoundException: String resource ID #0x2
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2913)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: android.content.res.Resources$NotFoundException: String resource ID #0x2
        at android.content.res.Resources.getText(Resources.java:348)
        at android.widget.Toast.makeText(Toast.java:307)
        at com.trojane.android.learnactivity.SecondActivity.onCreate(SecondActivity.java:19)
        at android.app.Activity.performCreate(Activity.java:7136)
        at android.app.Activity.performCreate(Activity.java:7127)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2893)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.app.ActivityThread.main(ActivityThread.java:6669) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 

 

而出错的代码是：

Toast.makeText(SecondActivity.this,getIntent().getIntExtra("initNum",1),Toast.LENGTH_LONG).show()

 

那么我们就看一下 makeText 方法的源代码：

public static Toast makeText(Context context, CharSequence text, @Duration int duration) {
        return makeText(context, null, text, duration);
    }

 

可以看到该方法中第二个参数的类型是 CharSequence 类型的， 那么CharSequence 是什么类型呢？我们可以看下图：

 

从上面这个图可以看出 CharSequence 是个接口类型，他的子类有我们熟悉的char、String、StringBuffer 等类型，应该说所有的字符类型都是直接或者间接实现了这个接口，

所以，对于makeText的第二个参数只能传入一个字符型。

 

原因： makeText 中第二个参数只能是CharSequence的直接或间接实现类，而传入的 int 类型的被认为是String Resource ID

解决方法：将 int 类型数值改成 String或其他字符型