Question

public class MainActivity extends Activity implements OnGestureListener 
{ 
   private LinearLayout mainlayout;
   private TextView tv;
   private GestureDetector gestureScanner;

   @Override
   public void onCreate(Bundle savedInstanceState) 
   {
       super.onCreate(savedInstanceState);

       gestureScanner = new GestureDetector(MainActivity.this,this);

       mainlayout = new LinearLayout(this);
       mainlayout.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
       mainlayout.setBackgroundColor(Color.GREEN);   


      tv = new TextView(getApplicationContext());
      tv.setBackgroundColor(Color.YELLOW);
      tv.setTextColor(Color.BLUE);
      tv.setGravity(Gravity.CENTER);   //here, why tv located top-left
      tv.setTextSize(20);
      tv.setLayoutParams(new LinearLayout.LayoutParams(320,80));
      mainlayout.addView(tv);
      setContentView(mainlayout);
  }
}

代码如上，我实现了xml以外的Java代码布局，添加了TextView，tv。使用tv.setGravity（Gravity.CENTER）来定位它，为什么我无法改变电视位置。我在等你的回答。先感谢您。我很感激你的善意。

Answer 1

您使用该代码设置TextView内容的重力，而不是TextView本身。尝试使用：

LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.FILL_PARENT);
lp.gravity = Gravity.CENTER;
tv.setLayoutParams(lp);

修改

事实证明，使用LinearLayout是可行的，但只有在更改方向并且在整个布局中只需要一个TextView时才有效：

private LinearLayout mainlayout; private TextView tv; @Override public void onCreate(Bundle bundle) { super.onCreate(bundle); mainlayout = new LinearLayout(this); mainlayout.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT)); mainlayout.setBackgroundColor(Color.GREEN); mainlayout.setOrientation(LinearLayout.VERTICAL); tv = new TextView(getApplicationContext()); tv.setBackgroundColor(Color.YELLOW); tv.setTextColor(Color.BLUE); tv.setTextSize(20); tv.setLayoutParams(new LinearLayout.LayoutParams(320, 80)); mainlayout.addView(tv); setContentView(mainlayout); LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT); lp.gravity = Gravity.CENTER; tv.setLayoutParams(lp); tv.setText("LOL"); }

上面的代码导致：

Answer 2

mainlayout = new RelativeLayout(this);
        mainlayout.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
        mainlayout.setBackgroundColor(Color.GREEN);

        tv = new TextView(getApplicationContext());
        tv.setBackgroundColor(Color.YELLOW);
        tv.setTextColor(Color.BLUE);
        tv.setTextSize(20);
        tv.setGravity(Gravity.CENTER);

        tv2 = new TextView(getApplicationContext());
        tv2.setBackgroundColor(Color.YELLOW);
        tv2.setTextColor(Color.BLUE);
        tv2.setTextSize(20);
        tv2.setGravity(Gravity.CENTER);

        RelativeLayout.LayoutParams params= new RelativeLayout.LayoutParams(320, 80);
        params.addRule(RelativeLayout.CENTER_IN_PARENT);

        tv.setLayoutParams(params);

        RelativeLayout.LayoutParams params2= new RelativeLayout.LayoutParams(320, 80);
        tv2.setLayoutParams(params2);


        mainlayout.addView(tv);
        mainlayout.addView(tv2);

        setContentView(mainlayout);

无法更改TextView实例的位置。

2 个答案: