如何使用onclick（）和按钮更改文本视图的文本颜色？

Question

ANSWERED

What I want to do is change the text color of a text view on a button press using onClick(). In my layout file, there's one text view and 2 buttons with android:onClick="onClick" attribute.

This is my code:

---

package ic.lunar.tictactoefree;

import android.os.Bundle;
import android.app.Activity;
import android.graphics.Color;
import android.view.Menu;
import android.widget.Button;
import android.widget.TextView;

public class SettingsActivity extends Activity {

TextView tv1;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.settings);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.settings, menu);
    return true;
}

public void onClick(Button b){
    tv1 = (TextView)findViewById(R.id.hello);
    if(b.getId()==R.id.grey){
        tv1.setTextColor(Color.RED);
    }
    if(b.getId()==R.id.white){
        tv1.setTextColor(Color.BLUE);
    }
}
}

---

now whenever I click any of the 2 buttons, the app force closes. What to do to make it work. I want to get the color changed according to the button pressed.

Answer 1

Change to

public void onClick(View v){ // method signature

Assuming you have buttons in settings.xml

android:onClick="onClick"  // for buttons in xml

Initialize in onCreate

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.settings);
    tv1 = (TextView)findViewById(R.id.hello);
}

And

public void onClick(View v){
    switch(v.getId())
    {
       case R.id.grey:
           tv1.setTextColor(Color.RED);
       break;
        case R.id.white:
           tv1.setTextColor(Color.BLUE);
       break;
    } 

}