按下按钮时应用程式停止运作

Question

So I am starting with app programming and I am trying to program my first test app. The main pupose of the app is that it acts like a dice and gives a random number between 1 and 6. However when I push the roll button the app crashes

My mainActivity code is as follows:

package com.example.second;

import java.util.Random;

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.EditText;


public class MainActivity extends ActionBarActivity {

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


@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;
}
public void roll(View v){
    int min = 1;
    int max = 7;

    Random r = new Random();
    int i1 = r.nextInt(max - min + 1) + min;
    EditText random = (EditText)findViewById(R.id.randomtxt);
    random.setText(i1);

}

@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);
 }
}

And the .xml code is

<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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.second.MainActivity" >

<Button
    android:id="@+id/roll"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:layout_marginLeft="106dp"
    android:layout_marginTop="124dp"
    android:onClick="roll"
    android:text="@string/roll" />

<TextView
    android:id="@+id/randomtxt"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/roll"
    android:layout_alignParentTop="true"
    android:layout_alignRight="@+id/roll"
    android:layout_marginTop="48dp"
    android:text="@string/num1"
    android:textAppearance="?android:attr/textAppearanceLarge" />

   </RelativeLayout>

The error that I get is Emulator] setWindowSurfaceColorBuffer: bad color buffer handle 0 , but I do not think this has anything to do with the crashing off the app.

And because I cannot find any problems (nor does SDK provide any) I have no idea why my app crashes.

Answer 1

You're trying to cast a TextView to an EditText . Either change your XML layout to define randomtxt as an <EditText> , or what you probably want is to just change this line:

EditText random = (EditText)findViewById(R.id.randomtxt);

to this:

TextView random = (TextView)findViewById(R.id.randomtxt);

You also probably want to change your setText line to:

random.setText(Integer.toString(i1));

Although there are many more options to cast you integer value to a String.

Answer 2

cast error textview to edittext and you cannot settext(integervalue) -> settext(String.valueof(integer))

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
         int min = 1;
            int max = 6;

            Random r = new Random();
            int i1 = r.nextInt(max - min + 1) + min;

            random.setText(String.valueOf(i1));

    }
});