Textchangedlistener的用法

  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) {

             }
         })

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) {

    }
});