我正在尝试了解 Android
的细节,但我发现了一些真正的挑战。我试图将 Button
链接到 TextView
,当您单击 Button
时,TextView
中的值会发生变化。我尝试使用我在网上找到的一些示例代码,但出现了很多错误,并且我不知道如何处理它们。如果您能提供任何帮助,我将不胜感激。
非常感谢您的帮助!
第 25 行:
Multiple markers at this line
- main cannot be resolved or is not a field
- R cannot be resolved to a variable
第 29 行:
btn1 cannot be resolved or is not a field
第 32 行:
Syntax error on token(s), misplaced construct(s)
第 34 行:
Multiple markers at this line
- Syntax error on token ")", ; expected
- Syntax error on token "(", ; expected
- void is an invalid type for the variable onClick
第 36 行:
txtVw1 cannot be resolved or is not a field
然后这是我的代码:
package com.demuro1.views;
import android.R;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list_item);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
Button aBut = (Button) findViewById(R.id.btn1);
public void changeText(){
mButton.setOnClickListener(new View.OnClickListener {
public void onClick(View v) {
final TextView mTextView = (TextView) findViewById(R.id.txtVw1);
mTextView.setText("Some Text");
}
};
}
}
然后是 View 中的xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<LinearLayout
android:layout_width="129dp"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:orientation="vertical" >
<TextView
android:id="@+id/txtVw1"
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="press button 1" />
<Button
android:id="@+id/btn1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:text="Button 1"
android:onClick="activateBtn1"/>
</LinearLayout>
<LinearLayout
android:layout_width="140dp"
android:layout_height="fill_parent"
android:layout_gravity="center_vertical"
android:orientation="vertical" >
<TextView
android:id="@+id/txtVw2"
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="press button 2" />
<Button
android:id="@+id/btn2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button 2"
android:onClick="activateBtn2"/>
/>
</LinearLayout>
</LinearLayout>
</LinearLayout>
最佳答案
使用以下代码
package com.demuro1.views;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final Button aBut = (Button)findViewById(R.id.btn1);
Button bBut = (Button)findViewById(R.id.btn2);
final TextView aText = (TextView)findViewById(R.id.txtVw1);
final TextView bText = (TextView)findViewById(R.id.txtVw2);
aBut.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
aText.setText("You Clicked Button 1");
}
});
bBut.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
bText.setText("You Clicked Button 2");
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
关于java - Android 中的按钮和 TextView,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/23176350/