Android：EditView统计用户输入的数量，限制输入！

无论是发帖，还是个人签名，为了防止刷屏，我们一般限制EditView输入的字数！

由于实现很简单，我直接上代码了：

<EditText
    android:id="@+id/ET"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text=""
    android:hint="个性签名"
    android:maxLength="32"/>

<TextView
    android:id="@+id/tv"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="32"
    android:textColor="@android:color/holo_blue_light"
    android:layout_gravity="right"/>

限制输入32个字，每输入一个就算显示剩余的输入数量，

然后超过32个字时将无法输入！

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.widget.EditText;
import android.widget.TextView;

public class TestOneActivity extends AppCompatActivity {
    private TextView hasnum;
    private EditText content;
    int num = 32;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_test_one);

        hasnum = (TextView) findViewById(R.id.tv);
        content = (EditText) findViewById(R.id.ET);

        hasnum.setText(num+"");
//监听事件

       content.addTextChangedListener(new TextWatcher() {
          private CharSequence temp;
          private int selectionStart;
          private int selectionEnd;

    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
    }


    public void onTextChanged(CharSequence s, int start, int before, int count) {
       temp = s;
     }

        public void afterTextChanged(Editable s) {
            int number = num - s.length();
            hasnum.setText("" + number);
            selectionStart = content.getSelectionStart();
            selectionEnd = content.getSelectionEnd();
            if (temp.length() > num) {
             s.delete(selectionStart - 1, selectionEnd);
            int tempSelection = selectionEnd;
            content.setText(s);
            content.setSelection(tempSelection);//设置光标在最后
         }
        }
        });
    }
}