android - java.lang.RuntimeException : Unable to instantiate activity ComponentInfo//java. lang.ClassNotFoundException 异常

Question

我是 android 新手，我正在开发一个非常简单的应用程序来练习。但我不知道为什么我不断收到这些错误。这是一个非常简单的应用程序，所以我不知道为什么它没有运行...

package com.tumta.salario;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {

EditText SalarioEdit;
Button Calcular;
TextView SalarioTotal;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    SalarioEdit = (EditText) findViewById(R.id.SalarioEditText);
    Calcular = (Button) findViewById(R.id.btnCalcular);
    SalarioTotal = (TextView) findViewById(R.id.SalarioTotalTextView);
}

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

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

public void onCalcular(View view){
    String SalarioText = String.valueOf(SalarioEdit.getText());
    double salarioTot = Double.parseDouble(SalarioText) * 12;
    SalarioTotal.setText(String.valueOf(salarioTot));

}

我的 LOGCAT:

 01-06 14:39:09.730: E/AndroidRuntime(5538): FATAL EXCEPTION: main
01-06 14:39:09.730: E/AndroidRuntime(5538): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.tumta.salario/com.tumta.salario.MainActivity}: java.lang.ClassNotFoundException: com.tumta.salario.MainActivity in loader dalvik.system.PathClassLoader[/data/app/com.tumta.salario-2.apk]
01-06 14:39:09.730: E/AndroidRuntime(5538):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1573)
01-06 14:39:09.730: E/AndroidRuntime(5538):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
01-06 14:39:09.730: E/AndroidRuntime(5538):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
01-06 14:39:09.730: E/AndroidRuntime(5538):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
01-06 14:39:09.730: E/AndroidRuntime(5538):     at android.os.Handler.dispatchMessage(Handler.java:99)
01-06 14:39:09.730: E/AndroidRuntime(5538):     at android.os.Looper.loop(Looper.java:130)
01-06 14:39:09.730: E/AndroidRuntime(5538):     at android.app.ActivityThread.main(ActivityThread.java:3691)
01-06 14:39:09.730: E/AndroidRuntime(5538):     at java.lang.reflect.Method.invokeNative(Native Method)
01-06 14:39:09.730: E/AndroidRuntime(5538):     at java.lang.reflect.Method.invoke(Method.java:507)
01-06 14:39:09.730: E/AndroidRuntime(5538):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:907)
01-06 14:39:09.730: E/AndroidRuntime(5538):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:665)
01-06 14:39:09.730: E/AndroidRuntime(5538):     at dalvik.system.NativeStart.main(Native Method)
01-06 14:39:09.730: E/AndroidRuntime(5538): Caused by: java.lang.ClassNotFoundException: com.tumta.salario.MainActivity in loader dalvik.system.PathClassLoader[/data/app/com.tumta.salario-2.apk]
01-06 14:39:09.730: E/AndroidRuntime(5538):     at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:240)
01-06 14:39:09.730: E/AndroidRuntime(5538):     at java.lang.ClassLoader.loadClass(ClassLoader.java:551)
01-06 14:39:09.730: E/AndroidRuntime(5538):     at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
01-06 14:39:09.730: E/AndroidRuntime(5538):     at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
01-06 14:39:09.730: E/AndroidRuntime(5538):     at        android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1565)
01-06 14:39:09.730: E/AndroidRuntime(5538):     ... 11 more

请帮帮我!提前致谢..

Answer 1

哦，说真的! public class MyActivity extends Activity!!!!! 永远不要扩展任何其他内容!!!!并在 list 中声明你的 Activity !(如果你刚刚创建它，如果不是，ide 将默认自动声明它)