我有两个活动(主要和计算器)。单击 main 中的按钮时,活动更改为计算器,但在 startActivity(intent) 运行时我不断收到错误
MainActivity.java
public class MainActivity extends Activity {
public final static String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";
public int mult = 1;
public int num1;
public int num2;
public int answer;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
public void calculator(View view)
{
Intent intent = new Intent(this, CalculatorActivity.class);
startActivity(intent);
}
}
CalculatorActivity.java
public class CalculatorActivity extends Activity
{
Button b0;
Button b1;
Button b2;
Button b3;
Button b4;
Button b5;
Button b6;
Button b7;
Button b8;
Button b9;
Button bDot;
Button bNeg;
Button bDiv;
Button bMult;
Button bSub;
Button bPlus;
Button bEnter;
EditText edit;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_calculator);
//Intent intent = getIntent();
//Intent intent = getIntent();
b0 = (Button) findViewById(R.id.button0);
b1 = (Button) findViewById(R.id.button1);
b2 = (Button) findViewById(R.id.button2);
b3 = (Button) findViewById(R.id.button3);
b4 = (Button) findViewById(R.id.button4);
b5 = (Button) findViewById(R.id.button5);
b6 = (Button) findViewById(R.id.button6);
b7 = (Button) findViewById(R.id.button7);
b8 = (Button) findViewById(R.id.button8);
b9 = (Button) findViewById(R.id.button9);
bDot = (Button) findViewById(R.id.buttonDot);
bNeg = (Button) findViewById(R.id.buttonNeg);
bDiv = (Button) findViewById(R.id.buttonDiv);
bMult = (Button) findViewById(R.id.buttonMult);
bSub = (Button) findViewById(R.id.buttonMinus);
bPlus = (Button) findViewById(R.id.buttonPlus);
bEnter = (Button) findViewById(R.id.buttonEnter);
edit= (EditText) findViewById(R.id.editText);
}
/** Called when the user clicks on a number */
public void enterNum(View view)
{
b0.setOnClickListener(new OnClickListener()
{
public void onClick(View view)
{
edit.setText(b0.getText().toString());
}
});
if(b0.isPressed())
edit.setText( b0.getText().toString() );
}
}