LogFragment.java

package com.javalive09.codebag.logger;

import android.graphics.Typeface;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ScrollView;

import com.javalive09.codebag.EntryTreeActivity;
import com.javalive09.codebag.R;

/**
 * Created by peter on 2017/3/22.
 */

public class LogFragment extends Fragment {

    private LogView mLogView;
    private ScrollView mScrollView;
    private boolean autoScroll;
    private static final long MAX = 20; //M

    public LogFragment() {
    }

    public View inflateViews() {

        ViewGroup.LayoutParams scrollParams = new ViewGroup.LayoutParams(
                ViewGroup.LayoutParams.MATCH_PARENT,
                ViewGroup.LayoutParams.MATCH_PARENT);
        mScrollView.setLayoutParams(scrollParams);

        mLogView = new LogView(getActivity());
        ViewGroup.LayoutParams logParams = new ViewGroup.LayoutParams(scrollParams);
        logParams.height = ViewGroup.LayoutParams.WRAP_CONTENT;
        mLogView.setLayoutParams(logParams);
        mLogView.setClickable(true);
        mLogView.setFocusable(true);
        mLogView.setTypeface(Typeface.MONOSPACE);

        // Want to set padding as 16 dips, setPadding takes pixels.  Hooray math!
        int paddingDips = 16;
        double scale = getResources().getDisplayMetrics().density;
        int paddingPixels = (int) ((paddingDips * (scale)) + .5);
        mLogView.setPadding(paddingPixels, paddingPixels, paddingPixels, paddingPixels);
        mLogView.setCompoundDrawablePadding(paddingPixels);

        mLogView.setGravity(Gravity.BOTTOM);

        mLogView.setTextAppearance(getActivity(), android.R.style.TextAppearance_Holo_Small);
        mScrollView.addView(mLogView);
        return mScrollView;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        mScrollView = (ScrollView) inflater.inflate(R.layout.scroll_view, container, false);
        mScrollView.setBackgroundResource(R.color.log_bg_color);
        View result = inflateViews();

        mLogView.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {
            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
            }

            @Override
            public void afterTextChanged(Editable s) {
                if(autoScroll) {
                    mScrollView.post(scrollToBottom);
                }


                int len = mLogView.getText().toString().getBytes().length;
                int currentLen = len /1024 / 1024; //M

                if(currentLen > ((EntryTreeActivity)getActivity()).getMaxLog()) {
                    clear();
                }

            }
        });
        return result;
    }

    private Runnable scrollToBottom = new Runnable() {
        @Override
        public void run() {
            mScrollView.fullScroll(ScrollView.FOCUS_DOWN);
        }
    };

    public void setAutoScroll(boolean autoScroll) {
        this.autoScroll = autoScroll;
    }

    public LogView getLogView() {
        return mLogView;
    }

    public void show(boolean show) {
        if (show) {
            getView().setVisibility(View.VISIBLE);
        } else {
            getView().setVisibility(View.GONE);
        }
    }

    public void clear() {
        mLogView.setText("---");
    }
}