Android 自定義View 實例

Android 相關自定義View基本知識可以參考 Android View 自定義屬性， 本篇博客博主將和大家一起實踐Android自定義View，我們知道，在應用中最常見的就是TitleBar，他們形式上保持一致，一般均是左邊回退按鈕，中間說明文本，右邊功能按鈕。所以很適合抽取作為自定義View模板，廢話少說，直接上干貨。

自定義View-attrs

自定義View類

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;

public class TitleBar extends RelativeLayout
{
    private Button mRightButton, mLeftButton;
    private TextView mCenterTextView;
    private int mCenterColor, mRightColor, mLeftColor;
    private Drawable mCenterBackground, mRightBackground, mLeftBackground;
    private float mCenterSize, mRightSize, mLeftSize;
    private String mCenterText, mRightText, mLeftText;

    public void setOnTitleBarClickListener(OnTitleBarClickListener mOnTitleBarClickListener)
    {
        this.mOnTitleBarClickListener = mOnTitleBarClickListener;
    }

    private OnTitleBarClickListener mOnTitleBarClickListener;

    public TitleBar(Context context, AttributeSet attrs)
    {
        super(context, attrs);

        final TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.TitleBarCustom);

        final int N = a.getIndexCount();

        for (int i = 0; i < N; i++)
        {
            int attr = a.getIndex(i);

            switch (attr)
            {
                case R.styleable.TitleBarCustom_center_color:

                    mCenterColor = a.getColor(attr, -1);
                    break;

                case R.styleable.TitleBarCustom_center_size:

                    mCenterSize = a.getDimension(attr, 0);
                    break;

                case R.styleable.TitleBarCustom_center_text:

                    mCenterText = a.getString(attr);
                    break;

                case R.styleable.TitleBarCustom_center_ground:

                    mCenterBackground = a.getDrawable(attr);
                    break;

                case R.styleable.TitleBarCustom_left_color:

                    mLeftColor = a.getColor(attr, -1);
                    break;

                case R.styleable.TitleBarCustom_left_size:

                    mLeftSize = a.getDimension(attr, 0);
                    break;

                case R.styleable.TitleBarCustom_left_text:

                    mLeftText = a.getString(attr);
                    break;

                case R.styleable.TitleBarCustom_left_ground:

                    mLeftBackground = a.getDrawable(attr);
                    break;

                case R.styleable.TitleBarCustom_right_color:

                    mRightColor = a.getColor(attr, -1);
                    break;

                case R.styleable.TitleBarCustom_right_size:

                    mRightSize = a.getDimension(attr, 0);
                    break;

                case R.styleable.TitleBarCustom_right_text:

                    mRightText = a.getString(attr);
                    break;

                case R.styleable.TitleBarCustom_right_ground:

                    mRightBackground = a.getDrawable(attr);
                    break;
            }
        }

        mRightButton = new Button(context);
        mRightButton.setText(mRightText);
        mRightButton.setTextSize(mRightSize);
        mRightButton.setTextColor(mRightColor);
        mRightButton.setBackgroundDrawable(mRightBackground);
        RelativeLayout.LayoutParams rightParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
        rightParams.addRule(ALIGN_PARENT_RIGHT, TRUE);
        rightParams.addRule(CENTER_VERTICAL, TRUE);
        rightParams.setMargins(0, 0, 10, 0);
        mRightButton.setLayoutParams(rightParams);
        addView(mRightButton);
        mRightButton.setOnClickListener(new OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                if (mOnTitleBarClickListener != null)
                {
                    mOnTitleBarClickListener.rightButtonClick();
                }

            }
        });


        mLeftButton = new Button(context);
        mLeftButton.setText(mLeftText);
        mLeftButton.setTextSize(mLeftSize);
        mLeftButton.setTextColor(mLeftColor);
        mLeftButton.setBackgroundDrawable(mLeftBackground);
        RelativeLayout.LayoutParams leftParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
        leftParams.addRule(ALIGN_PARENT_LEFT, TRUE);
        leftParams.addRule(CENTER_VERTICAL, TRUE);
        leftParams.setMargins(10, 0, 0, 0);
        mLeftButton.setLayoutParams(leftParams);
        addView(mLeftButton);

        mLeftButton.setOnClickListener(new OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                if (mOnTitleBarClickListener != null)
                {
                    mOnTitleBarClickListener.leftButtonClick();
                }

            }
        });

        mCenterTextView = new TextView(context);
        mCenterTextView.setText(mCenterText);
        mCenterTextView.setTextSize(mCenterSize);
        mCenterTextView.setTextColor(mCenterColor);
        mCenterTextView.setBackgroundDrawable(mCenterBackground);
        RelativeLayout.LayoutParams centerParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
        centerParams.addRule(CENTER_IN_PARENT, TRUE);
        leftParams.setMargins(10, 0, 10, 0);
        mCenterTextView.setLayoutParams(centerParams);
        addView(mCenterTextView);

        a.recycle();
    }

    @SuppressWarnings("unused")
    public void setRightButtonVisiablity(boolean isVisiable)
    {
        if (mRightButton == null) return;

        if (isVisiable)
        {
            mRightButton.setVisibility(View.VISIBLE);
        }
        else
        {
            mRightButton.setVisibility(View.GONE);
        }
    }

    @SuppressWarnings("unused")
    public void setLeftButtonVisiablity(boolean isVisiable)
    {
        if (mLeftButton == null) return;

        if (isVisiable)
        {
            mLeftButton.setVisibility(View.VISIBLE);
        }
        else
        {
            mLeftButton.setVisibility(View.GONE);
        }
    }

    @SuppressWarnings("unused")
    public void setCenterTextVisiablity(boolean isVisiable)
    {
        if (mCenterTextView == null) return;

        if (isVisiable)
        {
            mCenterTextView.setVisibility(View.VISIBLE);
        }
        else
        {
            mCenterTextView.setVisibility(View.GONE);
        }
    }

    public interface OnTitleBarClickListener
    {
        void leftButtonClick();

        void rightButtonClick();
    }
}

使用自定義View

首先在UI中定義

然後在代碼中使用

public class SixActivity extends Activity
{
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_title);

        initView();
    }

    private void initView()
    {
        final TitleBar titleBar = (TitleBar) findViewById(R.id.title_bar);

        if (titleBar != null)
        {
            titleBar.setOnTitleBarClickListener(new OnTitleBarClickListener()
            {
                @Override
                public void leftButtonClick()
                {
                    Toast.makeText(SixActivity.this, "Left button click!", Toast.LENGTH_LONG).show();
                }

                @Override
                public void rightButtonClick()
                {
                    Toast.makeText(SixActivity.this, "Right button click!", Toast.LENGTH_LONG).show();
                }
            });
        }
    }
}

這樣就完成了整個TitleBar的自定義View，雖然很粗糙，但是基本的模型已經出來了，這是個典型的組合自定義型View的例子，其他自定義型View後續會更新。