Android:字符左倒计时在EditText

Question

我有一个限制为150个字符的EditText:

 <EditText
    android:id="@+id/editText1"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#fff"
    android:layout_marginBottom="50dp"
    android:padding="30dp"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:maxLength="150"
    android:gravity="top|left"
    android:lineSpacingMultiplier="1.8"
    android:inputType="textMultiLine|textCapSentences" >
</EditText>

TextView:

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="100dp"
 />

NewActivity:

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.TextView;

public class NewActivity extends Activity {


private TextView textView1;
private EditText editText1;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.new_text);

    final ImageButton a = (ImageButton) findViewById(R.id.imageBack);
    a.setOnClickListener(new OnClickListener()  {
        @Override
        public void onClick(View arg0) {
            Animation anim =              AnimationUtils.loadAnimation(NewActivity.this, R.anim.animation);
            a.startAnimation(anim);
            Intent intent = new Intent(NewActivity.this,MainActivity.class);
            startActivity(intent);
            editText1.addTextChangedListener(new TextWatcher()
            {
                @Override
                public void onTextChanged(CharSequence s, int start, int before, int count)
                {
                }
                @Override
                public void beforeTextChanged(CharSequence s, int start, int count, int aft)                                                                           
                {
                }
                @Override
                public void afterTextChanged(Editable s)
                {
                   // this will show characters remaining
                    textView1.setText(150 - s.toString().length() + "/150");
                }
            });

        }
    });


}}

我想在页面的右上角创建一个小框，在那里你可以看到有多少字符剩下，例如132/150，我曾尝试在stackoverflow上查看其他解决方案，但我无法让它们工作。

Answer 1

你可以这样做

mEditText.addTextChangedListener(new TextWatcher()
{
    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count)
    {
    }
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int aft                                                                           
    {
    }
    @Override
    public void afterTextChanged(Editable s)
    {
       // this will show characters remaining
        countTextView.setText(150 - s.toString().length() + "/150");
    }
});

Answer 2

你可以使用texttwatcher来查看文本何时发生了变化

private TextView mTextView;
private EditText mEditText;
private final TextWatcher mTextEditorWatcher = new TextWatcher() {
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        }
        public void onTextChanged(CharSequence s, int start, int before, int count) {
           //This sets a textview to the current length
           mTextView.setText(String.valueOf(s.length()));
        }
        public void afterTextChanged(Editable s) {
        }
};

您可以使用

为edittext设置texttwatcher

mEditText.addTextChangedListener(mTextEditorWatcher);

Answer 3

像…

editText.addTextChangedListener(new TextWatcher() {
        @Override
        public void onTextChanged(CharSequence s, int start, int before,
                int count) {
            int length = s.length();
            // set this length/maxlength to the textview at the top left
            // corner
            textView.setText(""+length+ "/" +max);//which is placed at the top right corner
        }
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count,
                int after) {
            // TODO Auto-generated method stub
        }
        @Override
        public void afterTextChanged(Editable s) {
            // TODO Auto-generated method stub
        }
    });

Answer 4

1. 保留文本观察器并跟踪输入文本的长度。
Do MAX_LENGTH - yourTextwatcherString.length;
2. 根据计时器/甚至按下键，不断更新RHS顶部的视图(有几种方法可以做到这一点)。在更新视图之前，检查旧长度和新长度是否不相同。