用更新的TextView Android替换TextView

Question

我正在动态地在活动布局中添加一个TextView。该活动使用startActivityForResult从另一个活动获取值，然后动态创建textView并向其添加特定值。但问题是，当我再次获得值并返回到负责显示textView的活动时，同一个活动有一个update按钮，它没有更新该textView，而是在前面的textView下面添加了另一个textView，在布局中，它继续添加而不进行更新。我知道我们可以将它的可见性设置为gone，但是它是否也从布局的子元素中删除了textView，或者还有另一种方法来破坏文本视图并在那个地方创建另一个呢？

My onActivityResult方法：

protected void onActivityResult(int requestCode, int resultCode, Intent intentData) {
        // TODO Auto-generated method stub
        super.onActivityResult(requestCode, resultCode, intentData);
        if(requestCode == REQUEST_CODE && resultCode == RESULT_OK){
            locationLat = intentData.getDoubleExtra("LocationLat", 0.0);
            locationLng = intentData.getDoubleExtra("LocationLang", 0.0);
            location = locationLat + " "+locationLng;
            if(location != ""){
                Toast.makeText(this, location, Toast.LENGTH_LONG).show();
                lblName = new TextView(this);
                lblName.setText(location);
                lblName.setId(9);
                lblName.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT));
                LinearLayout ll = (LinearLayout) findViewById(R.id.llOne);
                ll.addView(lblName, 5);
                Button btnSetLoc = (Button) findViewById(R.id.getLoc);
                btnSetLoc.setText("Change Location");
            }
            else{
                Toast.makeText(this, "location is not set", Toast.LENGTH_LONG).show();
            }
        }
    }

Answer 1

尝试检查lblName是否为空，然后创建它，否则更新它

  protected void onActivityResult(int requestCode, int resultCode, Intent intentData) {
            // TODO Auto-generated method stub
            super.onActivityResult(requestCode, resultCode, intentData);
            if(requestCode == REQUEST_CODE && resultCode == RESULT_OK){
                locationLat = intentData.getDoubleExtra("LocationLat", 0.0);
                locationLng = intentData.getDoubleExtra("LocationLang", 0.0);
                location = locationLat + " "+locationLng;
                if(location != ""){
                    Toast.makeText(this, location, Toast.LENGTH_LONG).show();
                    if(lblName==null) {
                        lblName = new TextView(this);
                        lblName.setId(9);
                        lblName.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
                        LinearLayout ll = (LinearLayout) findViewById(R.id.llOne);
                        ll.addView(lblName, 5);
                        Button btnSetLoc = (Button) findViewById(R.id.getLoc);
                        btnSetLoc.setText("Change Location");
                    }
                    lblName.setText(location);
                }
                else{
                    Toast.makeText(this, "location is not set", Toast.LENGTH_LONG).show();
                }
            }
        }

Answer 2

确实要删除文本视图而不更改其值吗？

更改TextView的文本比从布局中删除TextView并重新附加新的文本要便宜得多

但是，如果您想要删除TextView并附加一个新的，您可以首先使用布局的removeView方法删除旧的，然后使用布局的addView方法插入新的

可以通过调用布局的indexOfChild方法来获取视图的索引

但是，如果您可以通过更改TextView中的文本来实现您正在尝试的目的，那么只需使用TextView的方法setText()

所以从根本上讲，这是什么

TextView oldText = (TextView) findViewById(R.id.oldText);
LinearLayout ll = (LinearLayout) findViewById(R.id.llOne);
int index = ll.indexOfChild(oldText);
ll.removeViewAt(index);
TextView newText = new TextView(context);
ll.addView(newText, index);

Answer 3

您需要更新runOnUiThread中的文本视图。

runOnUiThread：在UI线程上运行指定的操作。如果当前线程是UI线程，则立即执行该操作。如果当前线程不是UI线程，则该操作将被发布到UI线程的事件队列中。

参考：http://developer.android.com/reference/android/app/Activity.html#runOnUiThread(java.lang.Runnable)

在您的代码中实现：

protected void onActivityResult(int requestCode, int resultCode, Intent intentData) {
        // TODO Auto-generated method stub
        super.onActivityResult(requestCode, resultCode, intentData);
        if(requestCode == REQUEST_CODE && resultCode == RESULT_OK){
            locationLat = intentData.getDoubleExtra("LocationLat", 0.0);
            locationLng = intentData.getDoubleExtra("LocationLang", 0.0);
            location = locationLat + " "+locationLng;
            if(location != ""){
                 runOnUiThread(new  Runnable() { 
                public  void  run() { 
                   Toast.makeText(this, location, Toast.LENGTH_LONG).show();
                lblName = new TextView(this);
                lblName.setText(location);
                lblName.setId(9);
                lblName.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT));
                LinearLayout ll = (LinearLayout) findViewById(R.id.llOne);
                ll.addView(lblName, 5);
                Button btnSetLoc = (Button) findViewById(R.id.getLoc);
                btnSetLoc.setText("Change Location");
                } 
            }); 

            }
            else{
                Toast.makeText(this, "location is not set", Toast.LENGTH_LONG).show();
            }
        }
    }

有关runOnUiThread的更多实现：code.php?s=runOnUiThread