自定义RelativeLayout view实现布局。

在开发中，一个界面或者几个界面通常用到的基本UI都是相似的。这时候如果布局文件的话 往往会涉及到多个布局文件。我们更倾向于自定义的view。

UI：

public class WFFE_FilePickerView2  extends RelativeLayout implements WFIFormElementActivityResult{    private TextView mTxtTitle;    private ImageView mImgIcon;    private TextView mTxtValue;    private ImageView mImgArrow;    private WFFE_FilePicker2 element;    private static final int ID_TITLE_LABEL  = 0x1001;    private static final int ID_RIGHT_ARROW  = 0x1002;    private static final int ID_MIDDEL_IMG   = 0x1003;    private static final int ID_VALUE_TXT    = 0x1004;    public WFFE_FilePickerView2(Context context, WFFE_FilePicker2 filePicker) {        super(context);        this.element = filePicker;        this.initAttributes();    }    public WFFE_FilePickerView2(Context context, AttributeSet attrs) {        super(context, attrs);    }    @SuppressWarnings("ResourceType")    private void initAttributes() {        if (null == getContext() || null == element) {            return;        }        final int imgWidth = GlobalUtil.getPixelsByDp(getContext(), 20.0F);        //        // initializes this ViewGroup and all child views        //        LinearLayout.LayoutParams viewGroupLayoutParams = new LinearLayout.LayoutParams(                LinearLayout.LayoutParams.MATCH_PARENT,                LinearLayout.LayoutParams.WRAP_CONTENT);        ViewUtils.setMarginParams(                this.getContext(),                viewGroupLayoutParams,                true,                WFIFormElement.MARGIN_12DP,                WFIFormElement.MARGIN_5DP,                WFIFormElement.MARGIN_12DP,                WFIFormElement.MARGIN_5DP);        this.setLayoutParams(viewGroupLayoutParams);        this.setGravity(Gravity.CENTER_VERTICAL);        mImgArrow = new ImageView(getContext());        mImgArrow.setId(ID_RIGHT_ARROW);        mImgArrow.setImageResource(R.drawable.icon_right_arrow);        LayoutParams arrowParams = new LayoutParams(imgWidth, imgWidth);        arrowParams.addRule(ALIGN_PARENT_RIGHT);        arrowParams.addRule(CENTER_VERTICAL);        ViewUtils.setMarginParams(getContext(), arrowParams, true, WFIFormElement.MARGIN_5DP, 0, 0, 0);        mTxtTitle = new TextView(getContext());        mTxtTitle.setId(ID_TITLE_LABEL);        mTxtTitle.setTextSize(WFIFormElement.TEXT_SIZE_15SP);        LayoutParams titleParam = new LayoutParams(LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);        titleParam.addRule(ALIGN_PARENT_LEFT);        CharSequence titleText = GlobalUtil.appendHeadAsterisk(getContext(), element.isRequired(), element.label, Constants.GREEN);        mTxtTitle.setText(titleText);        mTxtValue = new TextView(getContext());        mTxtValue.setId(ID_VALUE_TXT);        LayoutParams valueParam = new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);        valueParam.addRule(LEFT_OF, mImgArrow.getId());        mTxtValue.setGravity(Gravity.RIGHT);        mTxtValue.setVisibility(GONE);        mImgIcon = new ImageView(getContext());        mImgIcon.setId(ID_MIDDEL_IMG);        LayoutParams iconParam = new LayoutParams(imgWidth, imgWidth);        iconParam.addRule(LEFT_OF, mTxtValue.getId());        mImgIcon.setImageResource(R.drawable.icon_right_arrow);        ViewUtils.setMarginParams(getContext(), iconParam, true, WFIFormElement.MARGIN_5DP, 0, WFIFormElement.MARGIN_5DP, 0);        mImgIcon.setVisibility(GONE);        View lineView = new View(getContext());        lineView.setBackgroundColor(Constants.GREEN);        LayoutParams lineParam = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 1);        lineParam.setMargins(WFIFormElement.MARGIN_5DP, WFIFormElement.MARGIN_5DP,                WFIFormElement.MARGIN_5DP, WFIFormElement.MARGIN_5DP);        lineParam.addRule(BELOW, mTxtTitle.getId());        this.addView(mTxtTitle, titleParam);        this.addView(mImgIcon, iconParam);        this.addView(mTxtValue, valueParam);        this.addView(mImgArrow, arrowParams);        this.addView(lineView, lineParam);        setupListener();    }    private void setupListener() {        if (null != mImgArrow && mImgArrow.getVisibility() == VISIBLE) {            mImgArrow.setOnClickListener(new OnClickListener() {                @Override                public void onClick(View view) {                    intentToFilePickerPage();                }            });        }    }    private void intentToFilePickerPage() {        Intent intent = new Intent(getContext(), BM_ContentChooserActivity.class);        intent.putExtra(BM_ContentChooserFragment.FILE_TYPE, BM_ContentChooserFragment.TypeFlag.FORM);        intent.putExtra(BM_ContentChooserFragment.CONTENT_SELECTED_ONE, true);        ((Activity) getContext()).startActivityForResult(intent, 1001);    }    @Override    public void handleActivityResult(int requestCode, int resultCode, Intent data) {        if (element.showIcon) {            this.mImgIcon.setVisibility(VISIBLE);        }        FileRecord fileRecord = (FileRecord) data.getSerializableExtra(BM_ContentChooserFragment.SELECTED_FILERECORD);        if (element.showValue) {            this.mTxtValue.setVisibility(VISIBLE);            this.mTxtValue.setText(fileRecord.name);        }    }}

开发中我们的习惯是（至少我的习惯是）：定义一个view 比如说 label  img text img。习惯是从左往右按顺序定义。这样的话 有时候很多UI不能实现。