自定义全局应用程序类与“android.app.Application无法转换”中断(Custom global Application class breaks with “android.app.Application cannot be cast to”)

 我有一个这样的自定义全局类 
 
import android.app.Application;

public class MyApp extends Application {

    public String MainAct;

    public String getMainAct() {
        return MainAct;
    }

    public void setMainAct(String mainAct) {
        MainAct = mainAct;
    }
}
 
 我想通过其onCreate方法中的另一个Activity保留此类中的字符串。 
 
    String local = "myLocalVariable";
    ((MyApp) getApplication()).setMainAct(local); //breaks here!!!
    String name = ((MyApp) getApplication()).getMainAct();
 
 它在标记行上发生错误： Caused by: java.lang.ClassCastException: android.app.Application cannot be cast to com.xxx.yyy.global.MyApp 
 
 我已经检查了代码五次，我无法找到任何错误。 谁能告诉我错误在哪里？ 
 
 谢谢 

I have a custom global class which looks like this
 
import android.app.Application;

public class MyApp extends Application {

    public String MainAct;

    public String getMainAct() {
        return MainAct;
    }

    public void setMainAct(String mainAct) {
        MainAct = mainAct;
    }
}
 
I want to preserve a string in this class via another Activity in its onCreate method. 
 
    String local = "myLocalVariable";
    ((MyApp) getApplication()).setMainAct(local); //breaks here!!!
    String name = ((MyApp) getApplication()).getMainAct();
 
It breaks on the marked line with error: Caused by: java.lang.ClassCastException: android.app.Application cannot be cast to com.xxx.yyy.global.MyApp
 
I've checked the code for five times and I cannot find error anywhere. Can anyone tell me where the error is?!
 
Thanks

原文：https://stackoverflow.com/questions/10607392