Android:设置EditText每行最大字符数? [英] Android: Setting EditText Max Chars per Line?

问题描述

有什么方法可以为EditText字段中的一行设置最大字符数? 我用TextWatcher尝试过，但是我不能真正做我想做的事.

Is there any way to set a maximum of Chars to a line in an EditText Field? I tried it with a TextWatcher, But I cant really do what I want.

我想设置每行最多行数和最多字符数.

I would like to set a maximum of lines and a maximum of chars per line.

示例:

插入的文本:

Lorem ipsum dolor sit amet consetetur sadipscing elitr.

结果(最大行数:10，每行最大字符数:20):

Lorem ipsum dolor
sit amet consetetur
sadipscing elitr.

编辑XML:

    <EditText
    android:id="@+id/edittext"
    android:layout_width="wrap_content"
    android:layout_height="200dp"
    android:layout_alignParentRight="true"
    android:layout_marginLeft="15dp"
    android:layout_marginRight="15dp"
    android:background="@drawable/bgedit"
    android:gravity="top"
    android:lines="11"
    android:paddingLeft="35dp"
    android:paddingTop="20dp"
    android:singleLine="false"
    android:inputType="textMultiLine" 
   />

推荐答案

以下过滤器每隔n个字符添加一个新行:

The following filter adds a new line after every n characters:

public class AutoWrapFilter implements InputFilter {
    private final int mLineChars;

    public AutoWrapFilter(int pLineChars) {
        mLineChars = pLineChars;
    }

    @Override
    public CharSequence filter(CharSequence src, int srcStart, int srcEnd, Spanned dest, int destStart, int destEnd) {
        CharSequence original = dest.subSequence(0,destStart);
        CharSequence replacement = src.subSequence(srcStart,srcEnd);

        if(replacement.length() < 1){
            return null;
        }

        int lastLineCharIndex = -1;

        for (int j = destStart - 1; j >= 0; j--){
            if(original.charAt(j) == '\n'){
                lastLineCharIndex = j;
                break;
            }
        }

        int charsAfterLine = lastLineCharIndex < 0 ? original.length() : original.length() - lastLineCharIndex;

        StringBuilder sb = new StringBuilder();

        for (int k = 0; k < replacement.length(); k++){

            if(charsAfterLine == mLineChars+1){
                charsAfterLine = 0;
                sb.append('\n');
            }

            sb.append(replacement.charAt(k));
            charsAfterLine++;

        }


        return sb;
    }

    public static void applyAutoWrap(EditText et, int wrapLength){
        InputFilter[] filters = et.getFilters();
        InputFilter[] newFilters = Arrays.copyOf(filters, filters.length + 1);
        newFilters[filters.length] = new AutoWrapFilter(wrapLength);
        et.setFilters(newFilters);
    }
}

用法:

public class MyActivity extends Activity{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        EditText edit = (EditText) findViewById(R.id.edit);

        AutoWrapFilter.applyAutoWrap(edit,10);

    }

}

结果:

此外，您可以添加更多代码以在单词开头添加换行符，以使其按单词换行.

Also, you can add more code to append new-line char at word beginning, to make it wrap by word.

这篇关于Android:设置EditText每行最大字符数?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！