private Button.OnClickListener calcBMI = new Button.OnClickListener()看不懂?package com.demo.android.bmi;import java.text.DecimalFormat;import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;public class Bmi extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
findViews();
setListensers();
}
private Button button_calc;
private EditText field_height;
private EditText field_weight;
private TextView view_result;
private TextView view_suggest;
private void findViews()
{
button_calc = (Button)findViewById(R.id.submit);
field_height = (EditText)findViewById(R.id.height);
field_weight = (EditText)findViewById(R.id.weight);
view_result = (TextView)findViewById(R.id.result);
view_suggest = (TextView)findViewById(R.id.suggest);
}
private void setListensers()
{
button_calc.setOnClickListener(calcBMI);
}
//?
private Button.OnClickListener calcBMI = new Button.OnClickListener()
{
public void onClick(View arg0)
{
DecimalFormat nf = new DecimalFormat("0.00");
double height = Double.parseDouble(field_height.getText().toString())/100;
double weight = Double.parseDouble(field_weight.getText().toString());
double BMI = weight / (height * height);
view_result.setText(getText(R.string.bmi_result) + nf.format(BMI));
//Give health advice
if (BMI > 25)
{
view_suggest.setText(R.string.advice_heavy);
}
else if (BMI < 20)
{
view_suggest.setText(R.string.advice_light);
}
else
{
view_suggest.setText(R.string.advice_average);
}
}
};
}
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;public class Bmi extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
findViews();
setListensers();
}
private Button button_calc;
private EditText field_height;
private EditText field_weight;
private TextView view_result;
private TextView view_suggest;
private void findViews()
{
button_calc = (Button)findViewById(R.id.submit);
field_height = (EditText)findViewById(R.id.height);
field_weight = (EditText)findViewById(R.id.weight);
view_result = (TextView)findViewById(R.id.result);
view_suggest = (TextView)findViewById(R.id.suggest);
}
private void setListensers()
{
button_calc.setOnClickListener(calcBMI);
}
//?
private Button.OnClickListener calcBMI = new Button.OnClickListener()
{
public void onClick(View arg0)
{
DecimalFormat nf = new DecimalFormat("0.00");
double height = Double.parseDouble(field_height.getText().toString())/100;
double weight = Double.parseDouble(field_weight.getText().toString());
double BMI = weight / (height * height);
view_result.setText(getText(R.string.bmi_result) + nf.format(BMI));
//Give health advice
if (BMI > 25)
{
view_suggest.setText(R.string.advice_heavy);
}
else if (BMI < 20)
{
view_suggest.setText(R.string.advice_light);
}
else
{
view_suggest.setText(R.string.advice_average);
}
}
};
}
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private class myListenner implements Button.OnClickListener
{
public void onClick(View arg0)
{
DecimalFormat nf = new DecimalFormat("0.00");
double height = Double.parseDouble(field_height.getText().toString())/100;
double weight = Double.parseDouble(field_weight.getText().toString());
double BMI = weight / (height * height);
view_result.setText(getText(R.string.bmi_result) + nf.format(BMI));
//Give health advice
if (BMI > 25)
{
view_suggest.setText(R.string.advice_heavy);
}
else if (BMI < 20)
{
view_suggest.setText(R.string.advice_light);
}
else
{
view_suggest.setText(R.string.advice_average);
}
openOptionsDialog2();
}
};
m_Button.setOnClickListener(caculation);
}
private OnClickListener calculation = new Button.OnClickListener()
{}一个菜鸟的理解: 这个问题真好,不知道会不会有更深入的探讨。
原来的接口,当对象用起来了。 后面之所以没有View. 或者Button. 觉得和强制转换差不多
private class myListenner implements EditText.OnClickListener
或
private TextView.OnClickListener calcBMI = new TextView.OnClickListener()
均没问题。看起来,像个修饰符。
Button继承view的,view有这个函数成员的
↳ android.view.View
↳ android.widget.TextView
↳ android.widget.Button
class Button{
OnClickListener tl;
public interface OnClickListener{
public void onClick();
}
public void setOnClickListener(OnClickListener l)
{
this.tl=l;
}
public void click(){
tl.onClick();
}
}
public class TestMain{
public static void main(String[] args){
Button b=new Button();
b.setOnClickListener(new Button.OnClickListener(){
public void onClick(){
System.out.println("buttonclick");
}
});
b.click();
}
}
相当于匿名内部类,在new Button.OnClickListener(){}的时候实现了一个匿名的类
[2011-08-10 07:41:27 - BMI] Installation error: INSTALL_FAILED_INSUFFICIENT_STORAGE
[2011-08-10 07:41:27 - BMI] Please check logcat output for more details.
[2011-08-10 07:41:28 - BMI] Launch canceled!
[2011-08-10 07:41:38 - BMI] Installation error: INSTALL_FAILED_INSUFFICIENT_STORAGE
[2011-08-10 07:41:38 - BMI] Please check logcat output for more details.
[2011-08-10 07:41:38 - BMI] Launch canceled!执行版主的例子出现这种错误是怎么回事??
为何Button.OnClickListener呢!