为什么我的应用程序按钮无法使用java导航到android studio中的下一页

Question

I am new to app development, I am stuck on this following example in my book.

Can some one please help me that why my play button is not working? After clicking on the play button the game should start and it should navigate to next activity.

Main page code

<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"
tools:context="com.packtpub.mathgamechapter3a.MainActivity">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="My Math Game"
    android:id="@+id/textView"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="25dp"
    android:textSize="30sp" />

<ImageView
    android:layout_width="150dp"
    android:layout_height="150dp"
    android:id="@+id/imageView"
    android:src="@mipmap/ic_launcher"
    android:layout_below="@+id/textView"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="38dp" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Play"
    android:id="@+id/buttonPlay"
    android:layout_marginTop="28dp"
    android:layout_below="@+id/imageView"
    android:layout_alignRight="@+id/button2"
    android:layout_alignEnd="@+id/button2"
    android:layout_alignLeft="@+id/button2"
    android:layout_alignStart="@+id/button2" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="High Scores"
    android:id="@+id/button2"
    android:layout_below="@+id/buttonPlay"
    android:layout_centerHorizontal="true" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Quit"
    android:id="@+id/button3"
    android:layout_below="@+id/button2"
    android:layout_alignRight="@+id/buttonPlay"
    android:layout_alignEnd="@+id/buttonPlay"
    android:layout_alignLeft="@+id/button2"
    android:layout_alignStart="@+id/button2" />
</RelativeLayout>

Java code

package com.packtpub.mathgamechapter3a;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;


public class MainActivity extends Activity implements View.OnClickListener{

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    final Button buttonPlay = (Button)findViewById(R.id.buttonPlay);
    buttonPlay.setOnClickListener(this);
}

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

}

Game page where it should navigate

<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"
tools:context="com.packtpub.mathgamechapter3a.GameActivity">


<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="2"
    android:id="@+id/textPartA"
    android:layout_alignParentTop="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_marginTop="24dp"
    android:textSize="70sp" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="x"
    android:id="@+id/textOperator"
    android:layout_alignTop="@+id/textPartA"
    android:layout_centerHorizontal="true"
    android:textSize="70sp" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="2"
    android:id="@+id/textPartB"
    android:layout_alignTop="@+id/textOperator"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"
    android:textSize="70sp" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="="
    android:id="@+id/textView4"
    android:layout_below="@+id/textOperator"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="92dp"
    android:textSize="70sp" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="2"
    android:id="@+id/buttonChoice1"
    android:layout_below="@+id/textView4"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_marginTop="99dp"
    android:textSize="40sp" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="4"
    android:id="@+id/buttonChoice2"
    android:layout_alignTop="@+id/buttonChoice1"
    android:layout_centerHorizontal="true"
    android:textSize="40sp" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="6"
    android:id="@+id/buttonChoice3"
    android:layout_alignTop="@+id/buttonChoice2"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"
    android:textSize="40sp" />
</RelativeLayout>

Java code

package com.packtpub.mathgamechapter3a;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;


public class GameActivity extends Activity implements View.OnClickListener{

int correctAnswer;
Button buttonObjectChoice1;
Button buttonObjectChoice2;
Button buttonObjectChoice3;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    //The next line loads our UI design to the screen
    setContentView(R.layout.activity_game);

    //Here we initialize all our variables
    int partA = 9;
    int partB = 9;
    correctAnswer = partA * partB;
    int wrongAnswer1 = correctAnswer - 1;
    int wrongAnswer2 = correctAnswer + 1;

    /*Here we get a working object based on either the button
      or TextView class and base as well as link our new objects
      directly to the appropriate UI elements that we created previously*/

    TextView textObjectPartA = (TextView)findViewById(R.id.textPartA);
    TextView textObjectPartB = (TextView)findViewById(R.id.textPartB);
    buttonObjectChoice1 = (Button)findViewById(R.id.buttonChoice1);
    buttonObjectChoice2 = (Button)findViewById(R.id.buttonChoice2);
    buttonObjectChoice3 = (Button)findViewById(R.id.buttonChoice3);

    //Now we use the setText method of the class on our objects
    //to show our variable values on the UI elements.

    textObjectPartA.setText("" + partA);
    textObjectPartB.setText("" + partA);

    //which button receives which answer, at this stage is arbitrary.

    buttonObjectChoice1.setText("" + correctAnswer);
    buttonObjectChoice2.setText("" + wrongAnswer1);
    buttonObjectChoice3.setText("" + wrongAnswer2);

    buttonObjectChoice1.setOnClickListener(this);
    buttonObjectChoice2.setOnClickListener(this);
    buttonObjectChoice3.setOnClickListener(this);


}//onCreate ends here

@Override
public void onClick(View view) {
    //declare a new int to be used in all the cases
    int answerGiven=0;
    switch (view.getId()) {

        case R.id.buttonChoice1:
  //initialize a new int with the value contained in buttonObjectChoice1
            //Remember we put it there ourselves previously
         answerGiven = Integer.parseInt("" + buttonObjectChoice1.getText());

            //is it the right answer?
            if(answerGiven==correctAnswer) {//yay it's the right answer
               Toast.makeText(getApplicationContext(), 
"Well done!", Toast.LENGTH_LONG).show();
            }else{//uh oh!
                Toast.makeText(getApplicationContext(),
 "Sorry that's wrong", Toast.LENGTH_LONG).show();
            }
            break;

        case R.id.buttonChoice2:
            //same as previous case but using the next button
    answerGiven = Integer.parseInt("" + buttonObjectChoice2.getText());
            if(answerGiven==correctAnswer) {
                Toast.makeText(getApplicationContext(), "Well done!",
Toast.LENGTH_LONG).show();
            }else{
                Toast.makeText(getApplicationContext(),
 "Sorry that's wrong", Toast.LENGTH_LONG).show();
            }
            break;

        case R.id.buttonChoice3:
            //same as previous case but using the next button
      answerGiven = Integer.parseInt("" + buttonObjectChoice3.getText());
            if(answerGiven==correctAnswer) {
                Toast.makeText(getApplicationContext(), "Well done!",
Toast.LENGTH_LONG).show();
            }else{
                Toast.makeText(getApplicationContext(),"Sorry that's wrong",
Toast.LENGTH_LONG).show();
            }
            break;

    }

}

}

Answer 1

well you need to do a if statement on the being clicked on.

if(view.getId() == R.id.buttonPlay)
{
Intent intent = new Intent(getBaseContext(), GameActivity.class);
startActivity(intent);
}

also make sure game activity is registered in the manifest file.

Answer 2

i checked your code it is correct .

I think you forget to register your activity in manifests

please check that

Answer 3

Intent in = getIntent();

is missing.. the 2nd activity should contain this line also add this

if(view.getId() == R.id.buttonPlay)
{
Intent inte = new Intent(MainActivity.this, GameActivity.class);
startActivity(intent);
}

and do register in the manifest file