Android Studio的Button控制元件的onClick屬性、setOnClickListener函式與OnClickListener介面用法
- onClick屬性
- setOnClickListener函式
- OnClickListener介面
添加點擊事件處理函式有三種方法，一個是在Xml檔案中添加onClick屬性，然后在代碼中添加對應的函式；二是直接在代碼中添加setOnClickListener函式；三是Activity通過implements實作OnClickListener介面，
onClick屬性
1、在Xml檔案中添加onClick屬性：
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:id="@+id/mybutton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:text="Press Me"
android:onClick="buttonClick"/>
</RelativeLayout>
在代碼中添加對應的函式：
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void buttonClick(View view) {
Toast.makeText(this, "Button was clicked", Toast.LENGTH_SHORT).show();
}
// ....
}
setOnClickListener函式
2、添加setOnClickListener函式
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button)findViewById(R.id.mybutton);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(MainActivity.this, "Button was clicked", Toast.LENGTH_SHORT).show();
}
});
}
}
OnClickListener介面
3、Activity通過implements實作OnClickListener介面
public class mainActivity extends Activity implements OnClickListener{
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
findViewById(R.id.Button02).setOnClickListener(this);
findViewById(R.id.Button03).setOnClickListener(this);
}
public void onClick(View view) {
switch (v.getId()) {
case R.id.Button03:
Toast.makeText(MainActivity.this, "Button was clicked", Toast.LENGTH_SHORT).show();
break;
case R.id.Button02:
Toast.makeText(MainActivity.this, "Button was clicked", Toast.LENGTH_SHORT).show();
break;
}
}
……
}
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