面临mainactivity困难

问题描述 投票:0回答:1

想在这里跑我的应用程序时,我面临着一些错误是logcat的

  java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.chatapp/com.example.chatapp.MainActivity}: java.lang.InstantiationException: java.lang.Class<com.example.chatapp.MainActivity> has no zero argument constructor
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2843)
    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: java.lang.InstantiationException: java.lang.Class<com.example.chatapp.MainActivity> has no zero argument constructor

这里是我mainAcivity`公共类MainActivity扩展AppCompatActivity {

Button login, register;

FirebaseUser firebaseUser;

@Override
protected void onStart() {
    super.onStart();

    firebaseUser = FirebaseAuth.getInstance().getCurrentUser();

    //check if user in null
    if (firebaseUser != null){
        Intent intent = new Intent(MainActivity.this, Main2Activity.class);
        new MainActivity(intent);
        finish();
    }

}

`

而且我认为这是一个错误

 public MainActivity(Intent intent) {

}
java android
1个回答
2
投票

活动不需要被实例化,所以你只需要调用下面开始一个:

//check if user in null
if (firebaseUser != null){
    Intent intent = new Intent(MainActivity.this, Main2Activity.class);
    startActivity(intent);
    finish();
}

基本上你只需要删除此行:

new MainActivity(intent);

并与启动活动:

startActivity(intent);
© www.soinside.com 2019 - 2024. All rights reserved.