Textchangedlistener的用法

 1  searchet.addTextChangedListener(new TextWatcher() {
 2             @Override
 3             public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
 4             }
 5 
 6             @Override
 7             public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
 8                 Toast.makeText(SearchActivity.this, charSequence, Toast.LENGTH_SHORT).show();
 9                 switch (charSequence.toString()){
10                     case "":searchtv.setText("取消");break;
11                     default:searchtv.setText("搜索");
12 
13                 }
14 
15             }
16 
17             @Override
18             public void afterTextChanged(Editable editable) {
19 
20             }
21         })

文字改变该方法就会调用,所以是个比较好用的方法.

需要注意的是 CharSequence text,即是显示的文字信息,:利用这个如下可以查看

Toast.makeText(SearchActivity.this, charSequence, Toast.LENGTH_SHORT).show();

searchet.addTextChangedListener(new TextWatcher() {
    @Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
    }

    @Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
        Toast.makeText(SearchActivity.this, charSequence, Toast.LENGTH_SHORT).show();
        switch (charSequence.toString()){
            case "":searchtv.setText("取消");break;
            default:searchtv.setText("搜索");

}

    }

    @Override
public void afterTextChanged(Editable editable) {

    }
});