android - textview设置 - textview是什么




android.content.res.Resources $ NotFoundException:字符串资源ID Main中的致命异常 (4)

我一直在尝试制作一个简单的程序,它取一个小的随机数并在textview中显示给用户。 在最终获得随机数生成(我认为)后,程序会在我运行时抛出致命异常。 代码没有错误,但我是一个完整的新手,我开始简单,以便我可以学习。 几个小时后,我已经提交寻求帮助。 我几乎可以肯定我的随机数字片段是在错误的区域,我只是不确定在哪里放。 我试过的每个地方都抛出同样的错误。

这是.java

package com.eai.vgp;

import java.util.Random;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.TextView;

public class MainActivity extends Activity {

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

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;

    }


    Random pp = new Random();
int a1 = pp.nextInt(10);

TextView tv = (TextView)findViewById(R.id.tv);{

tv.setText(a1);}

    }

XML

<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"
tools:context=".MainActivity" >

<TextView
    android:id="@+id/tv"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true" />

</RelativeLayout>

logcat的

03-03 16:34:25.313: I/Process(740): Sending signal. PID: 740 SIG: 9
03-03 16:35:02.212: E/Trace(806): error opening trace file: No such file or directory     (2)
03-03 16:35:02.802: W/ResourceType(806): No package identifier when getting value for     resource number 0x00000001
03-03 16:35:02.813: D/AndroidRuntime(806): Shutting down VM
03-03 16:35:02.813: W/dalvikvm(806): threadid=1: thread exiting with uncaught exception     (group=0x40a13300)
03-03 16:35:02.833: E/AndroidRuntime(806): FATAL EXCEPTION: main
03-03 16:35:02.833: E/AndroidRuntime(806): java.lang.RuntimeException: Unable to start     activity ComponentInfo{com.eai.vgp/com.eai.vgp.MainActivity}:     android.content.res.Resources$NotFoundException: String resource ID #0x1
03-03 16:35:02.833: E/AndroidRuntime(806):  at     android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
03-03 16:35:02.833: E/AndroidRuntime(806):  at     android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
03-03 16:35:02.833: E/AndroidRuntime(806):  at     android.app.ActivityThread.access$600(ActivityThread.java:130)
03-03 16:35:02.833: E/AndroidRuntime(806):  at     android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
03-03 16:35:02.833: E/AndroidRuntime(806):  at     android.os.Handler.dispatchMessage(Handler.java:99)
03-03 16:35:02.833: E/AndroidRuntime(806):  at android.os.Looper.loop(Looper.java:137)
03-03 16:35:02.833: E/AndroidRuntime(806):  at     android.app.ActivityThread.main(ActivityThread.java:4745)
03-03 16:35:02.833: E/AndroidRuntime(806):  at     java.lang.reflect.Method.invokeNative(Native Method)
03-03 16:35:02.833: E/AndroidRuntime(806):  at     java.lang.reflect.Method.invoke(Method.java:511)
03-03 16:35:02.833: E/AndroidRuntime(806):  at     com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
03-03 16:35:02.833: E/AndroidRuntime(806):  at     com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
03-03 16:35:02.833: E/AndroidRuntime(806):  at dalvik.system.NativeStart.main(Native     Method)
03-03 16:35:02.833: E/AndroidRuntime(806): Caused by:     android.content.res.Resources$NotFoundException: String resource ID #0x1
03-03 16:35:02.833: E/AndroidRuntime(806):  at     android.content.res.Resources.getText(Resources.java:229)
03-03 16:35:02.833: E/AndroidRuntime(806):  at     android.widget.TextView.setText(TextView.java:3620)
03-03 16:35:02.833: E/AndroidRuntime(806):  at     com.eai.vgp.MainActivity.onCreate(MainActivity.java:22)
03-03 16:35:02.833: E/AndroidRuntime(806):  at     android.app.Activity.performCreate(Activity.java:5008)
03-03 16:35:02.833: E/AndroidRuntime(806):  at     android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
03-03 16:35:02.833: E/AndroidRuntime(806):      atandroid.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
03-03 16:35:02.833: E/AndroidRuntime(806):  ... 11 more
03-03 16:35:05.113: I/Process(806): Sending signal. PID: 806 SIG: 9

a.setText(String.valueOf(x))

这是我案子问题的确切解决方案。


其他可能的方案:

tv.setText(Integer.toString(a1));  // where a1 - int value

移动

Random pp = new Random();
int a1 = pp.nextInt(10);
TextView tv = (TextView)findViewById(R.id.tv);
tv.setText(a1);

onCreate()里面,并改变tv.setText(a1); to tv.setText(String.valueOf(a1));

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

  Random pp = new Random();
  int a1 = pp.nextInt(10);

  TextView tv = (TextView)findViewById(R.id.tv);
  tv.setText(String.valueOf(a1));

}   

第一个问题:在onCreate()之前调用了findViewById() ,它会抛出一个NPE。

第二个问题:直接将int传递给TextView会调用重载方法来查找String资源(来自R.string )。 因此,我们希望使用String.valueOf()来强制String重载方法。


tv.setText( a1 + " ");

这将解决您的问题。





textview