My app keeps crashing on the mainActivity screen everytime I touch empty space on the screen. I have three buttons, two radioButtons, a textview, and two editText fields; whenever I touch these my app works fine, but if I ever touch white space, then the whole app crashes. I have minSDk of 15 and targetSDK of 23. I am adding Users to a database using SQLiteOpenHelper. Users have a name, password, and type (buyer or seller). Here is my code:
MainActivity.java
package com.example.cristiannavarrete.my_shopping;
import android.content.Context;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CompoundButton;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
// private String userName;
// private String userPass;
MyDBHandler db;
private Button logIn, addUser, clear;
private EditText userField, passField;
private RadioButton buyer;
private RadioButton seller;
//Singleton instance = Singleton.getInstance();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db = new MyDBHandler(this, null, null, 4);
logIn = (Button) findViewById(R.id.button);
addUser = (Button) findViewById(R.id.button2);
clear = (Button) findViewById(R.id.clear);
userField = (EditText) findViewById(R.id.editText);
passField = (EditText) findViewById(R.id.editText2);
buyer = (RadioButton) findViewById(R.id.radioButton);
seller = (RadioButton) findViewById(R.id.radioButton2);
logIn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (db.hasUser(userField.getText().toString())) {
Toast.makeText(getApplicationContext(), "Log In successful", Toast.LENGTH_SHORT).show();
}
else
Toast.makeText(getApplicationContext(), "Log In bad", Toast.LENGTH_SHORT).show();
}
});
addUser.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
User user = new User(userField.getText().toString(), passField.getText().toString(), "buyer");
user.setId(db.addUser(user));
Toast.makeText(getApplicationContext(), Integer.toString(user.getId()), Toast.LENGTH_SHORT).show();
}
});
seller.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (seller.isChecked())
buyer.setChecked(false);
}
});
buyer.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (buyer.isChecked())
seller.setChecked(false);
}
});
clear.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
db.deleteAllRows();
}
});
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<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" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity"
android:onClick="clear">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/LogIn"
android:id="@+id/textView"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="45dp"
android:textStyle="bold"
android:textColor="#5e00ff"
android:textSize="25sp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/UserName"
android:id="@+id/textView2"
android:layout_marginTop="42dp"
android:layout_below="@+id/textView"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:textStyle="bold" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/Pass"
android:id="@+id/textView3"
android:layout_below="@+id/textView2"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="60dp"
android:textStyle="bold" />
<EditText
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/editText"
android:layout_below="@+id/textView2"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="textPassword"
android:ems="10"
android:id="@+id/editText2"
android:layout_centerVertical="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/LogInButton"
android:id="@+id/button"
android:layout_below="@+id/editText2"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="29dp" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/AddUser"
android:id="@+id/button2"
android:layout_alignTop="@+id/button"
android:layout_toRightOf="@+id/textView"
android:layout_toEndOf="@+id/textView" />
<RadioButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/NewBuyer"
android:id="@+id/radioButton"
android:textSize="15sp"
android:layout_below="@+id/button2"
android:layout_centerHorizontal="true" />
<RadioButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/NewSeller"
android:id="@+id/radioButton2"
android:layout_below="@+id/radioButton"
android:layout_alignLeft="@+id/radioButton"
android:layout_alignStart="@+id/radioButton"
android:textSize="15sp" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/clearDatabase"
android:id="@+id/clear"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.cristiannavarrete.my_shopping" >
<application
android:name=".global"
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme" >
<activity android:name=".MainActivity" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".SellerMainPage"
android:label="Seller Main Page">
</activity>
<activity
android:name=".BuyerMainPage"
android:label="Buyer Main Page">
</activity>
<activity
android:name=".ItemInfoPage"
android:label="Item Info Page">
</activity>
</application>
</manifest>
Can anyone tell me why this happens. Thanks in advance for the help!
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Answer
Using in your layout the attribute
`android:onClick="clear"
you have to implement inside your Activity a method with the same name
public void clear(View v) {
// do something
}
The View passed into the method is a reference to the widget that was clicked.
When a user clicks the view, the Android system calls the activity’s clear(View) method.
Pay attention: if you are using a fragment, Android will not look for the onClick method in the fragment but only in the current Activity.
You can achieve the same using:
View myClickableView = findViewById(R.id.myView);
myClickableView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
clear(v);
}
});
public void clear(View v) {
// do something
}