Android Studio崩溃应用程序

debugcn 发表于 Dev

我对Android完全陌生，只是开始学习并开始一个项目。一切都很好，但是当我想单击“注册”按钮时，应用程序崩溃。我修复了一些错误，但这不能持续很长时间。也尝试调试，但不要低估调试器的内容。任何意见，请帮助

package com.example.demir.carsharing;

import android.content.Intent;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.Display;
import android.content.Intent;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {


    DatabaseHelper helper = new DatabaseHelper(this);
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }

    public void onButtonClick(View v){
        if (v.getId()==R.id.bLogin)
        {
            EditText a = (EditText)findViewById(R.id.TFUsername);
            String str = a.getText().toString();

            EditText b = (EditText)findViewById(R.id.TFPassword);
            String pass = b.getText().toString();

            String password = helper.searchPass(str);

            if(pass.equals(password))
            {
                Intent i = new Intent(MainActivity.this, Display.class);
                i.putExtra("Username", str);
                startActivity(i);
            }
            else
            {
                // DIsplay popup message
                Toast temp =Toast.makeText(MainActivity.this, "Username and Password don't match", Toast.LENGTH_SHORT);
                temp.show();

            }

        }
        if (v.getId()==R.id.bSignUpHere)
        {
            Intent i = new Intent(MainActivity.this, signup.class);
            startActivity(i);
        }

    }
}

这是一个日志文件

E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.example.demir.carsharing, PID: 3566
                  java.lang.IllegalStateException: Could not execute method for android:onClick
                      at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
                      at android.view.View.performClick(View.java:5610)
                      at android.view.View$PerformClick.run(View.java:22265)
                      at android.os.Handler.handleCallback(Handler.java:751)
                      at android.os.Handler.dispatchMessage(Handler.java:95)
                      at android.os.Looper.loop(Looper.java:154)
                      at android.app.ActivityThread.main(ActivityThread.java:6077)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
                   Caused by: java.lang.reflect.InvocationTargetException
                      at java.lang.reflect.Method.invoke(Native Method)
                      at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
                      at android.view.View.performClick(View.java:5610) 
                      at android.view.View$PerformClick.run(View.java:22265) 
                      at android.os.Handler.handleCallback(Handler.java:751) 
                      at android.os.Handler.dispatchMessage(Handler.java:95) 
                      at android.os.Looper.loop(Looper.java:154) 
                      at android.app.ActivityThread.main(ActivityThread.java:6077) 
                      at java.lang.reflect.Method.invoke(Native Method) 
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755) 
                   Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.demir.carsharing/com.example.demir.carsharing.signup}; have you declared this activity in your AndroidManifest.xml?
                      at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1805)
                      at android.app.Instrumentation.execStartActivity(Instrumentation.java:1523)
                      at android.app.Activity.startActivityForResult(Activity.java:4224)
                      at android.support.v4.app.BaseFragmentActivityJB.startActivityForResult(BaseFragmentActivityJB.java:48)
                      at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:77)
                      at android.app.Activity.startActivityForResult(Activity.java:4183)
                      at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:859)
                      at android.app.Activity.startActivity(Activity.java:4507)
                      at android.app.Activity.startActivity(Activity.java:4475)
                      at com.example.demir.carsharing.MainActivity.onButtonClick(MainActivity.java:53)
                      at java.lang.reflect.Method.invoke(Native Method) 
                      at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
                      at android.view.View.performClick(View.java:5610) 
                      at android.view.View$PerformClick.run(View.java:22265) 
                      at android.os.Handler.handleCallback(Handler.java:751) 
                      at android.os.Handler.dispatchMessage(Handler.java:95) 
                      at android.os.Looper.loop(Looper.java:154) 
                      at android.app.ActivityThread.main(ActivityThread.java:6077) 
                      at java.lang.reflect.Method.invoke(Native Method) 
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)

全能者

尝试执行以下操作：

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

    v = (Button) findViewById(R.id.bSignUpHere);
    v.setOnClickListener(SignUpOnClick);


}

View.OnClickListener SignUpOnClick = new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        Intent i = new Intent(MainActivity.this, signup.class);
        startActivity(i);
    }
};

您链接的错误是因为您没有在清单中声明所需的活动。

因此，在mainActivity下面的清单中添加了另一个decleration。

像这样：

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity
        android:name=".MainActivity"
        android:label="@string/title_activity_main"
        android:theme="@style/AppTheme.NoActionBar"></activity>

    <activity
        android:name=".signup"></activity>
</application>

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