1、点击Button改变页面背景色
通过Button改变页面背景色，首先新建相应的对象，让后绑定到Layout上的元素。
final RelativeLayout layout = (RelativeLayout)this.findViewById(R.id.layout);
final Button btnRed = (Button)this.findViewById(R.id.btnRed);
然后向新建的按钮增加单机事件。
btnRed.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
layout.setBackgroundColor(Color.RED);
((Button)view).setText("Is Red");
}
});
完整代码：
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setTitle("Button");
setContentView(R.layout.activity_main);
final RelativeLayout layout = (RelativeLayout)this.findViewById(R.id.layout);
final Button btnRed = (Button)this.findViewById(R.id.btnRed);
final Button btnGreen = (Button)this.findViewById(R.id.btnGreen);
final Button btnBlue = (Button)this.findViewById(R.id.btnBlue);
btnRed.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
btnGreen.setText("Green");
btnBlue.setText("Blue");
layout.setBackgroundColor(Color.RED);
((Button)view).setText("Is Red");
}
});
btnGreen.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
btnRed.setText("Red");
btnBlue.setText("Blue");
layout.setBackgroundColor(Color.GREEN);
((Button)view).setText("Is Green");
}
});
btnBlue.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
btnRed.setText("Red");
btnGreen.setText("Green");
layout.setBackgroundColor(Color.BLUE);
((Button)view).setText("Is Blue");
}
});
}
}
MainActivity.java
2、CheckBox状态获取
要获取CheckBox状态，只需要设置OnCheckedChangeListener()即可。
CheckBox chkBox = (CheckBox) findViewById(R.id.chkFootball);
chkFootball.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
if (b) strFootball = "Football";
else strFootball = "";
tvResult.setText(strFootball + " " + strBasketball);
}
});
完整代码为：
public class MainActivity extends AppCompatActivity {
private String strFootball = "";
private String strBasketball = "";
private TextView tvResult ;
private CheckBox chkFootball;
private CheckBox chkBasketball;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// this.setTitle("Button");
setContentView(R.layout.activity_main);
tvResult = (TextView) findViewById(R.id.tvResult);
chkFootball = (CheckBox) findViewById(R.id.chkFootball);
chkBasketball = (CheckBox) findViewById((R.id.chkBasketball));
chkFootball.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
if (b) strFootball = "Football";
else strFootball = "";
tvResult.setText(strFootball + " " + strBasketball);
}
});
chkBasketball.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
if (b) strBasketball = "Basketball";
else strBasketball = "";
tvResult.setText(strFootball + " " + strBasketball);
}
});
}
}
MainActivity.java
3、RadioButton与RadioGroup
要获取RadioGroup内RadioButton的选择状态，为RadioGroup添加选择事件即可。
rGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup radioGroup, int i) {
// TODO
}
});
首先在RadioGroup内创建两个RadioButton
<RadioGroup
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@+id/textView"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:id="@+id/rGroup"> <RadioButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="男"
android:id="@+id/rbMale"
android:checked="false" /> <RadioButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="女"
android:id="@+id/rbFemale"
android:checked="false" /> </RadioGroup>
然后，为RadioGroup设置OnCheckedChangeListener()
rGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup radioGroup, int i) {
if(i==rbMale.getId()) {
result.setText("你的性别是：男");
}
else if(i==rbFemale.getId()){
result.setText("你的性别是：女");
}
}
});
完整代码：
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView; public class MainActivity extends AppCompatActivity { private TextView result;
private RadioButton rbMale;
private RadioButton rbFemale;
private RadioGroup rGroup; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// this.setTitle("Button");
setContentView(R.layout.activity_main); result = (TextView)findViewById(R.id.textView);
rbMale = (RadioButton)findViewById(R.id.rbMale);
rbFemale = (RadioButton)findViewById(R.id.rbFemale);
rGroup = (RadioGroup)findViewById(R.id.rGroup); rGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup radioGroup, int i) {
if(i==rbMale.getId()) {
result.setText("你的性别是：男");
}
else if(i==rbFemale.getId()){
result.setText("你的性别是：女");
}
}
}); } }
MainActivity.java